1972 Maverick Sprint

[Maverick]

WXO and I took the Sprint to RPM, Inc -- well, at first we took it to where RPM, Inc USED to be. When I made the appointment last week, he failed to mention their MOVE. No sign on the old place saying where they went to. Didn't have their phone number, which didn't change. Borrowed a phone book from the business next door. They were helpful but wishing I'd get out of there.

Called RPM and got directions to an address for the new place. Got there about 20 minutes late for the appointment but felt NO guilt. They could have told me them moved.

So, after 20 or so minutes of waiting there, they got a good carburetor guy going on my dyno tune. Problem was he didn't get very far. Accelerator pump wasn't working because the check valve in the fuel bowl wasn't functioning. Maybe debris? (There was some in the fuel bowl..) Maybe something wrong with the seat? No way to know. With no way to get the accelerator pump working right he couldn't go on with the tune.

He did diagnose and fix the advance curve. With the vacuum advance connected the total timing was up to 40 degrees. Too much. He just removed the hose to the vacuum advance and the mechanical advance would pull it up to 30 degrees. He was happy with that.

I did get a printout of a WOT partial run. Enough to indicate what the torque curve is probably going to look like when its tuned. Pretty flat. HP was not impressive. It'll probably pick up some with the proper tune but I'M GONNA NEED MORE MOTOR!!! I'll get this one running decent but will be watching Craigslist and ebay for a Phase 2 motor.

Next step is to take one of my other used fuel bowls and try it. See if the acc pump will give a proper squirt with a different fuel bowl.

[Maverick]

I really love the way it turned out! Maybe someday I'll have the time to put into making a car look that good. I think it would be fun learning and doing.

I love that vintage car too. Just barely past the muscle car prime. IMO, there's a lot of really cool cars that came after '71.

-BP

Thanks!! Yes, fun learning and doing. Just need the time, place to work, and a few hobby bucks to spend. Spending rate sets the pace but that's OK.

The more I look at the Maverick the more I like the body lines. I even like the ride. The add-on rear sway bar and larger front bar probably stiffens it up some and makes it corner flat. Not much bounce or sway.

Just gotta get the inevitable bugs out. And, a PHASE 2 MOTOR!!

[Maverick]

Well, I may need a Phase 2 motor, but first I need more traction. Came off a stop sign, made a right turn, got it straight and nailed it. Spun that right rear 205X70X14 all the way thru first gear. Fun, but not very effective. I have two 235X60X15s and some American Racing Outlaw II wheels that need a lot of work. I expect they would help with the wheel spin. Gotta move those up in priority -- to next after the carb issues.

Tested a $12 tach I picked up (Carlisle or Charlotte?) and it works. I need to install it before I run it hard thru the gears. Autozone had a 4.5" hose clamp I needed to go around the steering column so a little wiring and it will be done.

[Maverick]

I'm still struggling with the carb. Tried another fuel bowl but it still stumbles when adding throttle. Found that the check valve under the acc pump nozzles was leaking down. I replaced that new valve with one from another carb and it helped a lot. Might be OK now but it still seeps a little. Moved the acc pump cam to the #2 position, which brings the squirt on immediately. Still stumbles so it must need a bigger squirt. Ordered a set of cams from Advance Auto and will pick them up in the morning. If a more aggressive cam doesn't do the trick I MAY order a set of nozzles and try some bigger ones.

I really don't like putting more money into this carb. I alternatively decide to buy one of these http://www.summitracing.com/parts/SUM-M08600VS/ and to try one more thing on my rebuild. Think I may be throwing good money after bad.

I'm told the Summit carb is a re-do of the Holley version of the Ford Autolite(?) 4100. Summit says it uses Holley jets, power valves, etc. Supposed to be a very good street carb.

[Fred32v]

A 750 cfm carb on a 302 cu.in. seems to me to be a little big,
especially without that loose converter and a deep gear.
I think I would have prefered a 600.
What is the size of the current Carb again?

[Maverick]

A 750 cfm carb on a 302 cu.in. seems to me to be a little big,
especially without that loose converter and a deep gear.
I think I would have prefered a 600.
What is the size of the current Carb again?

Right. I posted the wrong link. Went back and edited it for the right one.

Yes, 600. Current one I'm working on is a Holley 600 too.

[markss327]

Well, I may need a Phase 2 motor, but first I need more traction. Came off a stop sign, made a right turn, got it straight and nailed it. Spun that right rear 205X70X14 all the way thru first gear. Fun, but not very effective.

I strongly recommend a differential device of choice, to tie both wheels tougher.
Don't let the terminology get ya... Posi-trac, Locker, Anti-Spin... designs may differ, but the end result, is the pretty much the same -under torque, (acceleration), power is distributed equally, to both tires.
The 'one wheel peel', is just wrong. A 'Phase Two' motor, will just make this worse.

A spool or 'mini spool' mechanically locks both axles, not recommend for the street.

I believe we all had this conversation, a while back....

[Maverick]

I believe we all had this conversation, a while back....

Yes we did. Its on the phase 2 list.

Lots of options to consider, all pretty expensive. I'm watching for an 8" center section to bolt in but no deals yet. They're strong enough for anything I'll do but they're not easy to find.

I can get a 9" housing that's shortened for the Mav and accepts the 8" axles, brakes, etc for $275. Then pick up a more available 9" center section.

Mustang and Explorer 8.8" axles are plentiful and can be re-worked to fit.

Something will come along.

[Maverick]

The accelerator pump is working pretty well. Went to the Holley web site and read up a little on them. Learned that using the #2 screw position is NOT helpful for more early squirt. Just the opposite. So, back to #1 hole.

Picked up my kit of cams at Advance, found the listing of least-to-most aggressive, and put the most aggessive (brown) cam one. Not much improvement. Checked the size of my nozzles. They're 37s, which Holley says should have the larger capacity 50 cc pump kit to fully utilize. 37s should be big enough. Then found Holley's graph of cam lift curves. The brown cam is NOT the best cam for strong squirts off idle. Blue is better. Put that one on in #1 hole and it eliminated the hesitation.

Still have some flutter under light, steady throttle and some at idle. Bigger jets? Gotta do some more reading.

Found a solution to the wheel spin. Just need someone riding shotgun. Even slim little wifey is enough.

Got the tach installed and ran it at WOT till 1st-to-2nd shift at about 5500. That'll do.

[MostMint]

the Holley book has the cam profiles - blue is an aggressive one if I recall correctly.

My latest prediction is that you would make more horsepower with a 650 CFM carb - at least.

Are you planning to put a better engine under this carb? It'll need more CFMs.

[Maverick]

the Holley book has the cam profiles - blue is an aggressive one if I recall correctly.

My latest prediction is that you would make more horsepower with a 650 CFM carb - at least.

Are you planning to put a better engine under this carb? It'll need more CFMs.

In the ordered list of cams, brown is shown as the most aggressive.

Installation Notes
Accelerator pump shot relative to cam color from lightest to heaviest are as follows: White, Blue, Red, Orange, Black, Green, Pink & Brown

But, you have to look at the curves to see when the rise happens.

http://www.holley.com/data/Products/Tec ... mGraph.pdf

Blue is actually more aggressive than brown early in the throttle rotation. Then there's a yellow one that's really most aggressive but it didn't come in the kit. Think I'm good with blue.

Best case, I'll get this carb working well for the phase 1 motor and then a get bigger carb for a Phase 2 motor. That's why I keep coming back to try to make my current carb work. A carb I'd buy for this motor wouldn't be good for the next, assuming I ever get there.

[Basement Paul]

I believe for your setup, a 600 should work great. My 350 Vette ran 14.11 at 99mph with a 650 carb, and I ran the same carb on a slightly more mild 400 small block. If your 302 was HIGH compression, then I think a 650 would make more sense.
I saw an 8" posi unit with 3.50 gears at the Canfield swap meet for $375. So they're out there if you don't want to screw around with all that other stuff.

-BP

[Maverick]

I believe for your setup, a 600 should work great. My 350 Vette ran 14.11 at 99mph with a 650 carb, and I ran the same carb on a slightly more mild 400 small block. If your 302 was HIGH compression, then I think a 650 would make more sense.
I saw an 8" posi unit with 3.50 gears at the Canfield swap meet for $375. So they're out there if you don't want to screw around with all that other stuff.

-BP

That's a good price. All new is $700-$800. Need to pick one up sometime so I have it when I need it.

50 years ago my buddy had a Henry J with an Olds Tri-Power, cam, headers out the fenders, and slicks. It was SCARY!! His best was 13.90 at about 90 MPH. 60 ft time must have been great. He let me run it once on the track but the rear U-joint broke going into 2nd. Anyway, I'd sure like to see 13.90 some day in the Mav. Seems like a reasonable goal, 50 YEARS LATER! Phase 2.

[MostMint]

I think my memory of the blue was to use it with the 30 cc pump. Put more in faster but did not need the duration since the pump is smaller.

[Maverick]

The acc pump cam helped a lot off idle but it still bogs with light throttle going down the road. Reading up a little, there are lots of possible causes. One WXO suggested, and the book does too, is clogged idle transfer slots or their air bleeds. Another cause is too much of the idle transfer slots being exposed below the butterflys. So, off comes the carb AGAIN to check these things out.

Slots looked clean. Blew out the air bleeds again with carb cleaner. Thought I found the problem with too much idle transfer slots exposure but ... that was only when it was on the fast idle cam. Pull the cam out of the way and exposure looked to be in the recommended .040-.060 range.

So, maybe it DOES need bigger jets. All I have are 64s. Ordered a jet kit from JEGS that is supposed to ship today. Maybe I'll have it by the weekend.

Today I worked on the driver's door and left fender alignment. Haven't been happy with the fit on those panels and yesterday the door started to bind. Top hinge should be replaced but not sure if I can find one. Anyway, got those panels looking better and the door working freely again. I'll watch for a new hinge.