So I have a friend that's dragging me into a project car that he acquired from an Inlaw(I don't mind, I have been looking for a project). It's a '69 Chevelle, its basically a bare shell on a frame with wheels. No engine, no Trans, no interior, etc. The car originally had a TH350 mounted to a punched out 327 out of another car. Those unfortunately have been sitting out of the car in the elements for about 10 years. He doesn't want to reuse them, so we get to basically start from scratch with the drivetrain.
We've already agreed on a GM Performance ZZ4 350 crate motor, but the Trans is where we are stuck.
My opinion is to not bother dropping another TH350 in it but get a 200-4R or 700R4 to get that extra gear to squeeze a little mileage out of it. My friend agrees and would like to go that route.
My question is, are these newer transmissions the same length as the TH350? Or is there going to be some major mounting bracket changes we are going to have to make along with possible driveshaft length changes?
Thanks in advance. 
Simple answer is that it is a GM A-body. So that means about every conceivable bolt-in transmission crossmember is available in the aftermarket. So, all you really have to do is get a driveshaft made. It couldn't be any easier to swap from one trans to another.
In reply to Ranger50:
That's what I figured, I haven't done a lot of research on the aftermarket, I wasn't sure if someone sold any brackets for the different transmissions.
a 700R4 shouldn't be tough. Check out bowtieoverdrives.com
Put a Powerglide in it. Gas mileage is overrated. 
Until you put in a 4L80E and then program it to engage the OD band to make a 6 speed out of it....
Gearheadotaku wrote:
a 700R4 shouldn't be tough. Check out bowtieoverdrives.com
Thanks, that site looks helpful and their prices don't look bad at all.
Ranger50 wrote:
Until you put in a 4L80E and then program it to engage the OD band to make a 6 speed out of it....
If you are going automatic OD, this is the way to go. One thing, you will have to mod the floor for a 4L80E, not a lot but it won't clear as is.
200r4 is a perfectly fine transmission and can be built to handle a lot of power. You don't need all the electronic transmission management crap.
Ranger50 wrote:
Simple answer is that it is a GM A-body. So that means about every conceivable bolt-in transmission crossmember is available in the aftermarket. So, all you really have to do is get a driveshaft made. It couldn't be any easier to swap from one trans to another.
Having put a 700R4 in a late 60s A-body, you don't even need a custom crossmember, you just redrill the frame where the crossmember attaches.
3.73s with a 455 in a Cutlass is fun, especially with the 700R4's super low first gear. And then you also have overdrive for sane cruise RPM.
There's a company that even makes a new shift gate/PRNDL for the original floor shifter. The hardest part about the swap was getting the TV cable right, since nobody seemed to make anything that fit right, and we wasted time trying to make a bolt-together solution when we should have just started fabricating from the get-go. Unless you have a full manual valvebody, you really need the TV cable set up correctly. It alters pressure as well as shiftpoints.
for 700r4 to replace car th350(6" tailshaft) it's as simple as moving the crossmember holes back 3" and shortening the driveshaft 3".
the 88-92 700r4 has the stronger parts versus an early one, and you can still upgrade certain things like the sun shell. i have put a decent amount of power through stock ones and done fine.
i gather if he is throwing down cash for a zz4 then he can just plunk down more for a new trans, so i don't think we need to go into upgrade specifics. but the TV cable adjustment is vital. you'll smoke even a great built trans in short order with incorrect TV cable setting.
http://www.promotionpowertrain.com/GM_STICK.html
