Joeg

Hi Fellow Olds lovers. I'm thinking about putting in a 700r4 in my 1970 olds w-31. Don't worry, I don't have the original trans for it. But I'm wondering what this take? Will my crossmember work? Or do I have to drill new holes, or get a different cross member?
Also just to fill in the blanks the trans is out of a 90 chevy 4wd. But I've got all the parts figured out to swap it to 2wd. And maybe this trans isn't strong enough for a 455 with 350 hp and 440 ft lbs or torque?

70cutty

Is there a reason why you choose 7004r4 instead of 200r4?
200r4 bolts right up, no need for adapter or flex plate spacer.
Just curious as I am debating which way to go with my car.

Joeg

Hi there, I'm getting a deal on the 700r4 but on the research ive done it boils down to 50/50 on what i'm told that the 200r4 isnt strong enough. If I could confirm for sure that the 200 would work, I would go that route. Of course you can have the 200 built, but thats where people still tell me its to light duty of a trans. So that in a nut shell is where i'm at. Also it is more money to get or build the 200's because of the heavier/more durable parts needed to use it.

Grumbler

Let me guess. A chebby lover told you that, that 200's aren't *strong* enough? I and many others on this board run a 200R behind 455's with more torque than most chebby's could only dream about. Properly built they last. You have to build the 700 for a 455 too, it's no 350 SBC.
The 200R has a superior 1-2 gear ratio for the big Olds. The 700 has a steeper first gear to get the SBC's in motion, they need RPM to perform.
A 455 don't need no stinkin RPM to get rolling, they just need traction LOL.
Mine's a street car but I go to the track with it for fun and I've worn out a set of slicks over the years with that *light duty* 200R. Get the 200R, it bolts in

Joeg

Lol, I live in a smaller town where, I believe old cars are a lost art here in Grand Forks. There are only about 2 or 3 shops that will even talk to you about them. Thank you very much by the way for you input. Would you be able to tell me what parts need to be strengthened? And is there a kit that any company out their offers for the rebuild? Any info will be much appreciated. Thanks again.

70cutty

Check out http://www.ckperformance.com.

most likely I'll be ordering from them.

joe_padavano

Neither trans is particularly strong in stock form. The needed upgrades for either are well documented. As for swapping, the 200-4R is the same overall length as a TH350, so it fits right in and driveshaft remains the same. The crossmember must be moved to the TH400 position, but the holes are already drilled in the frame. You DO need to swap out the front and intermediate e-brake cables for those from a TH400 car due to the movement of the crossmember.

The 700R4 is a different overall length from other GM transmissions, so driveshaft mods are required. The crossmember is in a different place also, so holes may need to be drilled in the frame. And, of course, you need an adapter plate.

Grumbler

Myself no, I only know enough to be slightly dangerous in that field lol, but as Joe said this is common knowledge among transmission experts. The upgrades are commonly referred to as Grand National mods, after the kick *** turbo Buick they were built for. Here's an interesting link you can look at on the differences between the 200 and 700

http://www.hotrod.com/how-to/transmi...mission-build/

Joeg

thanks so much for the link. I think I found exactly what I need to build up the 200.

Joeg

Thanks for the insight. Especially on the brake cables part. I hadn't heard that part yet, and now i'll be prepared for it.

David DeCan

I talked with Art Carr about a 200 4R for my 70. Super nice guy and very helpful on the phone. I was sold, then I got a line on a 4 speed.
It was about a $2400 soup to nuts deal, converter included for a 500-600 HP 455 CI Olds torque monster. He told me a story about his Turbo Grand National Buick he still has in the back of the shop. 11-12 second car, able to freeway cruise at something like 2400 RPM. Art is not pushy either. I would absolutely consider buying a modified 200 4R from him in place of the 700 R4--if I was not doing the 4 speed conversion--big smile.

67442nut

FYI, when I converted my '67 CS 330 to 700R4,
I had to cut about 1/4" off the front lip of the cross member
so the back edge of the pan would clear the front edge of the cross member.
This was not mentioned in any of the research I did prior to doing the conversion.
My car has never been wrecked, so I don't think it's a misalignment problem.
Wasn't a major deal.
Made a clean straight cut with a sabre saw and dressed up the edge.
Looks original.

joe_padavano

Probably because most of what you read concerned a Chevy swap. Chevy crossmembers were tubular. Olds crossmembers are "hat section" stamped and thus wider.