Need help,
Have 1985 vette and want to change the present transmission 700R to a 400 series transmission. Has anyone done this in the past? What addtional parts and mods are needed to accomplish the change? Reason for the swap out , put the 700r in 1977 c3 vette for the over drive factor and reduction of RPM at higher speed, Other words consume less gas. Thanks for the help.

The 700 is a far better trans than the 400

Hello. There's a kit to install a TH350 in to a 85 vette, but I haven't seen any thing for a TH400 yet that will just bolt in. But I'm sure some one has done it.
David

I wouldn't do that if it were me.

As has already been said, the 700R is a much better trans than the 400. I got out of the busness before the 700R's came along, but I've built a lot of THM 400's, and also the THM 350's, I personally prefer the 350 to the 400 for strip and HiPref street use. The 400 is bigger and heavier...don't know if it would even fit up inside that C-3 without a lot of sheet metal work.
Why not just go out and buy another 700R for the C-3 ?