GM 3.8 V6 Interchange?

[Maverick]

Got the bolt pattern/tranny issues under control. There are three relevant bolt patterns for our tranny search.
1. Known by four names: Metric, S10, 60 Degree V6, and Small Corporate. Used in the Camaro, FireBird, and S10 60 degree V6s.
2. Chevy. Used in the 90 degree V6s (except our 3800 FWDs) and Chev V8s.
3. BOP (Buick/Olds/Pontiac)

All of Willdy's 3800s have the 60 degree/Metric pattern.

The only 4-speed, RWD,OD, lockup TQ transmission with the metric pattern is the TH700r4s that came in the V6 Camaros, Firebirds, and S10 v6s (not 4.3L) It also comes with a different case to fit the Chevy V8 pattern.

The TH200r4 is another 4-speed, RWD, OD, lockup TQ AT. It comes in only one case but has a dual (Chevy and BOP) bolt pattern.

On the Raleigh Craigslist there was a 60 degree TH700r4 with 22K miles on a rebuild out of a 2.8 Firebird for $100. Unfortuniately, the shipping to Tucson was about $175. Still a good deal but Willy has cheaper options.

He has a TH200r4 (also a RWD, 4-speed, OD, lockup TQ) and picked up a TH700r4 with the V8 pattern for $50.

So, now he has two transmissions that he can use if he builds an adapter and a friend that's eager to machine one for him. If they build the adapter to the V8 pattern, they will be able to bolt up either the TH200r4 or the TH700r4.

We have blueprints that show the dimensions for the BOP and Chevy V8 bolt patterns but CANNOT find the dimensions for the 60 degree pattern. I've searched the internet and a few forums but am coming up empty. Willy's friend really wants the factory specs - he'll locate those holes dead on and doesn't want to deal with measuring worn dowl and bolt holes.

The other thing I'd really like to find is a description of 3800 factory balancing. I can't find anything that says if the 3800s are balanced externally (think they are) or internally. Or if all 3800s have the same internal imbalance. Don't know if we have to worry about mismatched flexplates or harmonic balancers.

If anyone has any ideas on where to find info on the metric pattern dimensions or 3800 balance I'd appreciate it.

[Fred32v]

You my already know this, but in 1988, GM began installing an internal balancing shaft in the 3800's.

[Maverick]

Yes, I learned about that little wierdo.

We have the dimensions for the 60 degree bolt pattern. It was in the newer (1994) edition of "Chevrolet Power" book.

Still looking for info on rotating assembly balancing for Series 1 and pre-Series 1 3800s. Got conflicting info on Series 2 and 3 and none on Series 1. Don't know which is worse.

[MostMint]

So how did it come to pass that a Toyota truck and GM 3.8 are getting put together? Is it as simple as that's what was laying around? Inquiring minds want to know why.

What is the budget of this project anyway - if you care to share?

for the record, I had one of those automatics - the 4 speed that attaches to the 60 degree V6. I bought an 85 Camaro parts car with a rod knock for $200 in 1996 I think. I'm sure I sold it but can't recall what it fetched.

[Maverick]

To understand Willy's project you'll have to know a little about him. My "big" brother is about 5'6" and is now down to about 125 lbs because of some severe health problems. Willy started building hot rods when he was about 16. Early ones included a '32 Ford coupe with top removed and body channelled (lowered over the frame). He had one or two other duece coupes, one with a 4 cyl (Model B) engine that would blow away V8s. Also put a flathead V8 in a '48 Plymouth convertable. etc, etc, etc.

I'll brag on him and say he's a mechanical genius. He figures out stuff that I can't understand when he explains it. Willy now lives on an air park (subdivision with an air strip) in the AZ desert South of Tucson. He has a hangar big enough for a few planes and a couple of projects and always has projects in process. He's made a living for a few decades repairing airplanes and buying and selling things.

I guess the project came about because Willy likes Toyota pickups and has one that needs an engine. He has ideas about lowering and moving the body back on the frame.

Its hard to say what the budget for the Toyota project is. Willy buys stuff cheap with an idea of how he might use it and sells at a profit if things go a different way. e.g., he picked up a fresh 351 Cleveland for $100. He may have been thinking I might use it in the Maverick. When I started rebuilding my 302 HO he sold the 351C for $500. I know he bought a S10 60 degree standard trans, bell, etc for $50 that he'll resell assuming one of the auto ODs work out.

Willy has a barter system going with a junk yard. They give him anything he needs and can find there. He insisted on paying something for the TH700r4 that he picked up there for $50. Those two transmissions are the only things I know of that were bought for this project. One or both will be resold (he already had a Th200r4 that might get used).

He has a friend that teaches auto mechanics in the high school. That school has a lot of equipment. The friend will take some of Willy's things to the school shop and get the students to work on them. e.g., put a block in a cleaning tank or paint a motorcycle frame.

The friend that will machine the adapter for him has big, industrial machine shop equipment and Willy has material on hand to build the adapter.

This is old school hot rodding and Willy is the quintessential hot rodder. He'll probably have to buy some bolts but that might be the total budget when he's done.

[johnsons63]

hi guys im new here... im having a hard time finding a cheap GM performance parts on the net... do you know any websites that has good prices for GM parts?...
____________________________

Still finding a good GM Performance Parts online shop that i can have a good deal...