GM transmission

[SOLER]

GM transmission for 1970 Oldsmobile

I'm looking for someone that is pretty much an expert on the following topic. Please refrain from the "I think it might" and "maybe it will fit" comments. Thanks



I have a 1970 Olds Vista Cruiser with a 455 and TH400 transmission. I am going to restore the car this summer, and want an overdrive. I don't want a Gear Vendor's unit. Can I get a 700R4 to fit? The engine will going to have around 450-500 horsepower when I get done with it. I'm going to do a mild rebuild on it. 450 hp seems more realistic. Will I have to get an adapter, or did GM put these trannies in BOP? Can I get a 4L80E to work? Are there parts out there to make the electronics work? I know they are pricey, and I could do a Gear Vendor's and be done with it.



Right now, my 12 bolt posi has 2. 56 gears in it, and I want to go with 3. 73 to get a little better launch. Those tall gears are great for the hiway, but crap off the line. So, I want the best of both worlds.



Can anyone shed some light here for me?



Thanks a bunch



SOLER

 

[mcoleman]

The 200R4s like were in the Grand Nationals are stronger for performance usuage when built by a good transmission guy. There are bunches of those out there with the BOP bolt pattern and many different places with expertise and parts for building them. We have ran them behind many 500+hp GNs and 455 Buicks with good success. I'm pretty positive that the 4L80E was never produced with the BOP bolt pattern but TCI use to sell an adapter for 50. 00 to allow them to work. I use to put 455 Buicks in all of my GM 4X4 trucks. Better mileage than the 350 and 400s and much more torque and power.

 

[SOLER]

Thanks. Are they stronger than a 700? Or is it pretty much the same transmission, just what BOP called it? Also, how hard is it to change out the indicator on the column? Will I use the same crossmember, or am I going to have to re-fab the frame?



Thanks again



SOLER

 

[mcoleman]

They are stronger when built correctly. Some of the Viper guys have even used that transmission when converting to an auto. Although they have less torque than modified Grand National or 455. On the 70-72 Buicks we were able to slide the cross-member up and redrill the holes. And install a 200R4 mount on the old cross-member. Ckperformance is one of the companies. I'll see if I can find links to others.

 

[KBennett]

Vista Cruiser's are cool. I had a '72 with the 350-2 barrel and it was a lot of fun. It's on the "wish I never sold it" list along with the '72 Cutlass.