1975 Corvette

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MostMint
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1975 Corvette

Post by MostMint »

Bought the car at an estate sale auction on 6/11/05 - paid $3900. It is a 1975 Corvette coupe with the L48 350, and a turbo 400 tranny. It is dark red metallic with black interior.

It barely ran - but I am fairly sure they wanted it to start at sale time. It idled real rough and backfired quite a bit. All the owner said was that he had not owned it long, the brakes were weak and the frame was solid in front of the rear wheel where they rust out.

There were a couple other bidders, but I wasn't watching them - I was busy deciding if I wanted to go higher. It was a good thing they did not go higher or I would not have gotten the car. Without a test drive I was not sure I wanted to spend $4000. "A 1975 Corvette for $3900" sounded reasonable to me.

After the auction I found a branch of my bank and completed the transaction that day. The car auctions started at noon and by 2:15 I had the title in my hand.

While I was waiting for the other auctions to finish, and for the owner to notarize the title, I started scoping out what I just bought. I asked some questions of the owner. He indicated that he had to adjust the timing to get it running, and made a gesture like he was advancing the timing.

The owner did not suggest driving it home because the brakes were weak. After the auction was over I moved it off the yard onto the driveway. I understood what he was talking about. The pedal was so soft, and the engine was idling so high there was no hope for the brakes to stop the car.

Initially I planned to pick it up on Sunday or Monday, but as soon as I got home I knew I wanted to bring it home that night. My wife went along with it and we went to get it after supper. Since I am not a big fan of the wrecker, I decided to give it a go myself. I packed up some brake fluid, spark plugs and tools. My wife and kids would get me there and I drafted my friend John to help me get it home.

I showed up at the car at about 7:30 that evening. In about an hour I had put air in the tires, topped off the brake fluid (which did not help) and radiator fluid, changed the plugs, adjusted the timing and idle, and was ready to go. These amateur prior owners had the wrong heat range plugs, and half of the wires were not properly secured to the plug (you know - the click). By now this Vette was starting to sound pretty good. I took it up and down the street. The brakes were weak, but would stop the car. Fortunately the headlights came up (as it was getting dark).

It was low on gas so we stopped at a nearby gas station. I had only driven the car two minutes when we pulled in. Immediately when I get out of the car some kid says "Nice car". I said thanks - laughing to myself. Out on the road two minutes and already got a compliment. It's nice but not that nice.

I learned a few more things on the trip - the wipers did not work! It had started sprinkling rain - good thing it stopped. The secondaries on the carb would not open. I had noticed the choke blade was missing so no doubt the choke mechanism on the Q-jet was not allowing the secondaries to open. I also noticed the exhaust was scraping the road on every tiny bump. But it tracked straight and felt pretty solid on the road.

It was my first time driving a Corvette - and the seating is different than any car I owned before.

Since my gravel drive has a high spot in the middle I drove the car over the grass to get it to the house.

It has not been out since, but more on that next time.
Last edited by MostMint on Mon Aug 22, 2005 12:36 pm, edited 2 times in total.
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Post by MostMint »

The easy part was over. I spent most of the next week completely mind locked – not knowing where to start. Spent a lot of time looking at the car and trying to figure out what I just bought and what to do with it.

At the time I bought it I had intended to drag race it. Fiberglass body had to make the car light – right? Wrong. According to the numbers I have it’s curb weight when new was 3529 lbs - only 25 pounds light than my Trans Am. Maybe this is why I don’t see many of them at the drag strip. Further complicating matters is the independent rear suspension which will undoubtedly be challenging when facing the power needed to run 12’s (or .1 faster than Dave – whatever that is LOL).

I could also make it my summer time daily driver – though it will need lots of TLC to get there. I would have to give up the stick shift but I am pretty sure it would be worth it to upgrade from a Camaro to a vintage Corvette.

The last option is to sell it after I make a lot of the necessary mechanical repairs. I am fairly sure I am money ahead on this numbers matching car.

Whatever option I choose I knew the next thing to do was make it drivable. There were several areas needing attention to achieve that:

Brakes
Fuel line
Windshield wipers
Seat belt
Oil change
Exhaust system too low

Brakes: Spent a lot of time reading about this on the Corvette Action Center forum. Seems there are problems like too much runout on the rotors that can cause the system to take in air, also problems with the proportioning valve. I considered them but then decided to just bleed the darn thing and see if that fixes it. I did some gravity bleeding and that helped but the pedal got real firm after bleeding with an assistant holding the pedal down.

During the brake work I also reconnected the brake light sensor on the proportioning valve to the wiring harness. After doing so I lost all electrical on the car! I decided this was probably a bad ground – found and cleaned connections on the ground between the frame and the firewall (or at least the metal part of it) and the problem was cured. As a bonus the inside courtesy lights now worked when opening the passenger door (not the light switch or driver door, but it’s a start).

Fuel line: Some genius had replaced the entire fuel line with rubber, along with the return line. Some of it was hanging down from the car – about an inch off the ground. I used some zip ties to get that part up off the ground to get it home. I never run cars with that much rubber in the fuel line.

For the pump to carb section, I bought a pre-bent stainless line. Replaced the rubber and inline fuel filter with that. Since it had an inline filter, I assumed there would be no fuel filter in the carb. I searched through my Q-jet parts inventory for the spring that holds the filter but could not locate one. Before I started taking apart the old parts carbs I decided to check in the Corvette’s carb for the spring – and it was there along with a beat up filter. I guess two filters are better than one!

For the tank to pump section I was able to utilize about 2/3 of the original lines which were still in the car. The section from near the fuel pump to just behind the passenger seat was still there. Apparently someone had cut the line there since the passage from there back was too small to fit the hose and the original steel lines. Argh. It took some work to get the lines cut cleanly (they had used tin snips and collapsed the line at the opening). I think the remaining steel line was there because they were unable to get the bolts/clips holding the line off because the frame and floorpans were too close to fit a regular wrench.

The last section from the steel line to the pump required a pre-bent rubber hose. The area was way too small to fit a straight hose. I tried and it kinked up. So I bought the correct hose from Corvette Central and was back in business.

The ironic part is that the problem was probably the hose between the tank and the steel, and none of the steel would have needed replaced. All of the steel brake lines appear original and in good shape, and the sections of the fuel line that were still in there were in very good shape.

Windshield wipers: The original problem was the wipers were catching on the hood. This was caused by replacement wipers with too high a profile. I corrected this by getting proper profile wipers from NAPA. The wipers were hitting each other, and I fixed this by adjusting the wiper linkage (fancy that it was adjustable!).

Seat Belt: I tried to save the original seat belt on the driver side, but the retractor mechanism for the lap belt was too rusted (this car came with two retractors). I tried to save it but soon discovered there was rust in places I could not adequately clean to get the retractor to work properly. You can buy just about every part for this Corvette from Ecklers or Corvette Central, but not the correct seat belts. The correct belts are discontinued. All you can get are lap belts with no retractor (think middle seat belt on most cars), which was not to my liking. On ebay the correct belts are going for $600 a pair or more. So I searched the Corvette Action Center forum to see what others were doing. Found a guy who had replaced his belts with those from a 4th gen Camaro – he said use the back belts. After scoping them in my Camaro, bought one at a junk yard for $35. On the coupe Corvette there is a loop that secures to the pillar to guide the seat belt. Installed that loop on the Camaro belt and put it in the car. The passenger belt was completely gone – replacing it will wait for the right price at a swap meet.

Oil change: There was gas in the oil when I bought the car. Too bad I did not notice this before bidding – might have been able to save myself a few hundred $ by scaring away the other bidders. I changed the oil and filter to correct this. I suspect the problem was from flooding when trying to start. But to be sure I checked the fuel pump for leaks and changed the carb (in case it was leaking down when not running)

Exhaust system too low: When dropping the tank to install the all rubber fuel line, the aluminized exhaust was cut just under the rear differential. When it was reassembled, they neglected to get the old pieces to butt up against each other. There was about a 2” gap inside the sleeve they had used. This lengthened the exhaust and left it hanging less than 1” from the ground. Every bump it scraped, even when going into the garage. I bought a 2 ½” ID pipe and connected them back together, with a jack lifting on the supply side of the pipe. This moved it up off the ground at least another inch. The rest will be gained by putting the right height tires on the car.

Now the car was ready to go.
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MostMint
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Post by MostMint »

My Corvette is an L48, and one of 33+ thousand coupes produced in 1975. Based on the VIN, I am guessing it was built on the first or second work day of January, 1975. I was almost 8 years old.

This Corvette is nowhere near original. I have spent a lot of time looking at it and learning. Here is what I know so far:

- The car did not have a lot of options. A/C, power steering and brakes, automatic transmission. It has the apparatus on the steering wheel for the telescoping column but I have not been able to get that to work yet.

- The trim tag says the interior should be silver vinyl (14V). It is now black. You can see the silver showing through the black on many of the inside trim pieces, so I am quite confident that it was silver at one point. They must have used some cheap vinyl paint and it scratches fairly easily. Even the remaining seatbelt was silver, and the paint/dye they used was coming off in a lot of places. The seats are not the right vintage – and I can see they were gold before they too were painted black. The engine ID tag on the center console indicates the engine has 270 lbs-ft of torque – this is incorrect for 1975.

- The trim tag says the exterior should be silver (13). It is now dark red metallic. I had a hard time believing it was ever silver. I could not find any evidence that this car was silver – until last night. Believe me I had looked everywhere – under trim pieces, bottoms of the door hinges, etc. Finally the silver revealed itself under the driver side door panel last night. It has been painted the dark red metallic at least twice – you can see the red overspray from the second application in the wheel wells, on the wiring harness, and tape marks (they masked off the door jam when painting the rear quarter panel). The most recent application came in 1997 or later – as I found a 1997 quarter under the seat with read overspray on it.

- The rear bumper cover is from a 76, 77 or 78 model. It has a one piece plastic Corvette emblem. The 75 had individual chrome letters and the cover was recessed for each letter. The original urethane covers are dried up and cracked by now so it is very hard to find one that is still original. I can get the correct replacement new for about $320.

- I believe the front clip is not original. There is no evidence of any color but the dark red on it, so it was probably not used. It was not a 75 clip though as the holes for the front emblem (between the headlights in front of the hood) are not in the correct location. They were filled in before it was painted but you can still see them. Furthermore there is an extra hole that is half covered by the Stingray emblem on the driver side. There are extra sockets in the front wiring harness (use not yet determined), and the front running light lenses are out of a 73. I also noticed some welding on the frame – where the lower control arm is attached to the frame. It appears to be recent and relatively low quality, so I can’t imagine why it was done. Also one of the 6 bolts holding the bumper assembly to the frame is not original.

- The engine block and VIN do match. The louvers on the decklid are consistent with a 1975 Corvette.

- The air conditioning compressor and brackets are missing. The A/C lines are there though they were cut once for no apparent reason.

- Lots of other parts were pilfered off the car. The radio comes on and finds stations but no sound comes out – probably because it had speaker boxes in the back and they were cut. The jack is missing. The hard plastic backs on the seats are missing. The passenger side seatbelt must have been working as it too was taken.

- I checked on the OHIO BMV website, and found the title had transferred six times since June 1999. The website has info online back to 1993, but this car did not change hands in Ohio from 1993 through May 1999. Four of the transfers were in 1999. Between then and now about 2000 miles were put on the car. It has 99,700 and change miles on it right now.
o I have requested a full chain of titles from the BMV and expect that info in a couple weeks.

- I am guessing the car was probably pulled out of a garage in 1999, some hack mechanics made some repairs (rubber fuel line etc) to get the thing running, put some fresh red paint on it and then sold it. Maybe the interior was repainted at that time. It probably traded hands a few times during this process.
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MostMint
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Post by MostMint »

Some repairs from last week:
- The carb would not open all the way when flooring the accelerator. This was probably because it has the wrong carb. I overcame this by securing the throttle linkage to the carb in a hole closer to the pivot point (where the cruise hooked to the carb). It was not the correct carb so I am not too concerned about this temporary fix.
- The left directional was not working, as the running light in the front was out. I was able to correct this by cleaning up the ground connection in the socket.
- Bought the new Firehawk Indy 500's, P225/70/R15 and put two of them on the two rally rims I bought, and then on the car. Car looks way better with the taller tires (27.5" tall vs. 24.75" on the old tires) and they fit in the wheelwell nicely. While I had the wheels off I took the opportunity to adjust the exhaust as I had sagged down to 2" off the ground. I jacked up the exhaust and tightened the clamps on the sleeve I had added, though I think I'll need a weld to get it to hold properly.

Weekend update:

Took it out on the freeway for a short test Friday night. The regular size rear tires and cleaned window glass warranted a test drive. Pressed the brakes with some force a couple times - it stops pretty well. I also smelled the brake smell as I am still cleaning the surface rust off the rear rotors. Afterward I noticed some brake fluid on a plug wire. The master cylinder was leaking at the back. So I bought a new master cylinder Sat. and installed it Sun.

Also fixed the radio - basically it was not attached to the speakers. There was some coax line out cables and some long wires from the back to all the speakers in the front. At one time there must have been an amp and rear speakers in the back of the car, and all the lines to and from were cut. So I reconfigured that to work with the radio. The radio now works - sound is not that great but better than nothing.

Also took the opportunity to do some additional clean up work under the dash on the passenger side. Freed up the vent control on the passenger side, added some clips so I could put back the screws that hold the right side of the dash front on. Installed the courtesy light back into its original bracket. Also made an attempt to fix the light for the wiper controls. I also confirmed that all of the dash parts were removed for painting and reinstalled quite hastily. Some parts (like some of the ductwork) are missing.

Installed the license plate bracket on the front and the historical plates that came in the mail on Saturday. I had bought the bracket on ebay but only recently became convinced that nothing was missing underneath.

Up next are new engine mounts and adjusting the steering gear box, as it has a little play in it.
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MostMint
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Post by MostMint »

Update:

I fixed the switch on the driver door that turns on the courtesy light. It just needed cleaned – too bad I bought a new one. I chose not to install it since the end was plastic and did not look like the original.

I also installed the support springs for the headlights – replacing three broken springs. I had bought them on my last order from Corvette Central.

I was prepared to buy some rims and other things at the Randolph swap meet. I was disappointed as there was only one set of 15x8 rally rims and they were already sold. The pair I bought at Canfield last month for $40 a piece are starting to look like a good deal. Since then I have been trying to buy some on ebay. Man ebay is killing the swap meets – there were so many empty spaces it was pathetic.

I did buy a new set of stock lug nuts ($10) and a seven blade clutch fan (also $10).

I also got detoured into polishing the car. I picked up the buffer from my Dad and was compelled to try it. The paint has a lot of water stains (either acid rain or mineral deposits from prior owners water supply). I also learned the car must have a clear finish as no red came off on the pad when polishing. The shine is good. The flaws in the paint are obvious – lots of nicks and a lot of bubbling paint on the hood and tops of doors. In spite of these flaws the car will look great from 10 feet. There is still more work to do here – after that it will be back to mechanical problems.

Also, I have a line on some seat belt parts that are needed to set up the passenger seat belt, and also a possible line on A/C parts.

And finally – I got the results back from my letter to the Ohio BMV. Not much info on the form since a federal law prohibits disclosure of private individuals info. The only thing I learned is that prior to 1999 the car was titled in North Carolina! So I have the forms from North Carolina DOT and plan to send them in soon.

Now I can add “southern car” to numbers matching in my description of the car. 8)
Last edited by MostMint on Tue Apr 18, 2006 12:35 pm, edited 1 time in total.
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Basement Paul
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Post by Basement Paul »

Too much to list!
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MostMint
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Post by MostMint »

Well not much action since last week.

After completing the polish job I washed it for the first time and took some pics. Need to post them.

Also drove it to work last Friday for the first time. Had no problems getting to work and back.

I did notice a squeak in the back when first starting to move the car.

The second set of rims are due to arrive today, and I finally sent a letter to the North Carolina DMV to see what I can learn about its history there.

Finally I did start looking at the problem with the fan hitting the shroud. It hits when you accelerate hard off the line and on the gear shifts under full power. The shroud is cracked and this is allowing the opening for the fan shroud to be distorted. The shroud is closer to the fan on the passenger side than the driver side, and the top is closer to the fan than the bottom. I don’t think changing the engine mounts will fix this problem. The current fan is 18” diameter flex fan. The stock size is 17 ½”, and no doubt this is contributing also.

Since the Camaro lost a synchro on 2nd gear, I am hesitant to start pulling things apart in case I need to drive the Vette for a few days while I am fixing or replacing the Camaro tranny.
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Post by MostMint »

Update 8/22:

As expected the rims arrived on the 17th. The paint on the rims is acceptable and they were basically rust free. Put the tires on them and installed them on the car that night. Each had a small ding in the outside edge of the rim. I corrected one with a hammer and a drift – the other did not respond to the treatment. The ding does not affect the bead so I put the tires on anyway. I was afraid I would have problems getting them to inflate since the rims are 8” and the tires are for rims up to 7.5”. This problem did not materialize as they inflated real easy. I installed them on the car that night.

Also put some touch up on the nicks. The color I bought is my guess at matching since they did not have any 1975 colors, and I am not going to spend $16 for a touch up bottle. The color does not cover that well, so I applied several coats. It matched pretty well after several coats applied.

I drove it to work again. It ran fine but I am now definitely getting a clunk in the rear at low speeds – under 5 mph. Sounds like a CV joint, so I am guessing a u-joint in one of the half shafts is going. I think this needs fixed before I take it to work again.

Also had to tighten the ground at the battery to get it to start. I think the bolt to hold on the cable is stripped. At least I hope it is the bolt and not the battery. I have replacement bolts.

Taking the t-tops off and back on is a hassle compared to my 95 Camaro. The Camaro has a nice built in rack in the back making storing real easy. The Vette requires bags and there is no place to work. Getting the tops in and out of the back is no easy task either. Oh well the price I pay for style I guess.

I also like the handling. I think there is a good chance it will be better than my Camaro once the suspension has been refreshed.

Edit: Here is a pic shortly after polishing the car: Corvette
Last edited by MostMint on Wed Sep 07, 2005 12:08 am, edited 4 times in total.
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wxo
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Post by wxo »

Andy,
Great gearhead reading over my breakfast coffee! Impressive picture, too! Too bad is was a bag of sh__ when you started.
-Walt
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MostMint
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8/29 update:

Post by MostMint »

Adjusted the steering gear box – what an improvement! I had more than an inch of free play in the steering wheel, now there is practically none. It only took 2 minutes to do.

Fixed the leaky header on the passenger side. The bolts holding the y-pipe to the cast iron header were slightly loose, and well rusted. Fortunately I was able to remove them without breaking the studs. Cleaned the threads off and reinstalled new nuts with never-seize. Those flowmasters sound pretty good without the exhaust leak. Now I just need to get rid of that flex fan.

While the car was up on jacks in the front I replaced the front stabilizer links. The old ones came right off without breaking, but the rubber parts were completely shot. I would have reused the original bolts and washers except the passenger side bolt was bent. I will put them in the save box in case the next owner wants to go back to the “original” parts.

Noticed the radiator cans are touching metal edge of the frame. I am not sure why – maybe because someone put a four-core in the car, maybe it was not put back quite right after an accident in the front. This will have to be addressed before too long.

Also noticed the passenger side engine mount is probably still original and needs replaced.

Replaced the bolts on the battery cables, since one of them was stripped.

Greased the driveshaft u-joints, but the rear-end clunk persists. I have several theories and plan to start work on this soon.
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History Detective?

Post by MostMint »

The N. Carolina DMV responded to my request for information. I can now safely say that this car found its first owner in Charlotte, North Carolina. It was titled on 2/12/75. According to these records it had six owners in North Carolina. It had 94811 miles on 11/15/88 – it currently has 99,900 and change. Most of the prior owners have three names – one of them goes by Billy Ray, though the first two owners were females. The document stack also included copies of titles for name changes and issuing of a new title after loans were paid off.

After Charlotte it lived in Winston Salem and Lexington before moving north to Ohio in 1997 or 1998.

For some reason I did not get the title copy for the last North Carolina owner, just a copy of the application for a title. Nonetheless he bought it on 3/24/97.

I am not sure if there is anything more to do with this info. I would like to know who changed the color and the interior so I have to decide if I am going to try to contact any of these people.

When I started this I had no idea how many states I would hve to go through to get to the original owner. Turns out it was just two.
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Post by MostMint »

This project has been on hold. I had the car on jacks and was ready to start disassembly when the Camaro tranny started its problems.

I plan to change the u-joints on the halfshafts first. The clunking is deifintely the halfshaft hitting the yoke on the center section. I am guessing these u-joints are original and probably have more stress on them than driveshaft ujoints since there seems to be some inward pressure on them from the suspension. It may be slight but would add up after 99K miles and 30 years.

I did buy a carb from a 75 Vette on ebay (yes correct Rochester part number) for about $80, and a factory air cleaner assembly for about $110. I don't have an install timetable for these yet, but it is a step in the direction of "all original".
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Post by MostMint »

This stint of mild weather has got me back on task. Today I pulled the half-shafts out. They came out real easy - all I had to do was unbolt them from the differential and the spindle and they came out. The instructions I had read made it sound much worse.

I also removed the inner u-joints for replacement. They seemed to be in pretty good shape - at least until they got ruined during disassembly. But it got me to thinking that they may not be the problem. I am starting to think the parts might not be original. I went looking for the GM part number on the shafts, and instead found "Spicer" and a part number cast into the yoke on the differential side. Interestingly the right and left have different part numbers.

I wonder if these are original parts. They have been in there a long time, I know that much. At any rate, I think I can radius the inside of the differential yoke on both sides and stop the contact between the two yokes.

Also, the driver side yoke on the differential has about 3/8" play (moving in and out). The other side is 1/8" or less. I am sure the 3/8" is too much and something inside needs replaced. However, the differential cover is bolted to way too many things to attempt to address that today. I think I need to remove the leaf spring in the back in order to remove the differential cover.

After all this is done, I have another problem. Last time I drove it I noticed some backfiring at higher RPM. I think the catalytic is starting to get blocked or the EGR on the passenger side exhaust is closing up. Argh. Old cars need work.
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Post by MostMint »

After some delay I worked on the car this week. I installed the new inner u-joints and put it back together. They felt better than the old ones and I wanted to know if they would fix the problem. It did not fix the problem however. It appears they are hitting about 45 degrees from the bottom of the rotation, toward the front of the car. It is almost like the trailing arms are too far forward, or the center section is too far back. More next time...
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]
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MostMint
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finally some pics

Post by MostMint »

Some pics....

Image

Image

Image
Last edited by MostMint on Sun Jun 17, 2007 8:22 pm, edited 1 time in total.
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