engine swap question

[785cole]

hey everyone, got a quick question. I just bought a 1983 Grand Prix, and id had a V6 in it stock. well i have a 400 out of a 1974 grand am that i am attempting to squeeze in the prix, and was wondering if anyone could offer any advice on this subject. i know that there is going to be some welding and fabrication involved, but what have i got myself into???

[MagicRat]

This is acutally a reasonable and easy swap. The '79 to '81 GP with the 301 cid V8 (Pontiac sourced) should provide you with many usable parts, like engine mounts, radiator hoses, radiator cradle, Y-pipe, rad, etc, since the 301 and your 400 were, externally identical.

It would be very easy if you were to start with a 301-equipped GP.

If you need parts etc, select parts for the '81 GP with a 301, since that model is most similar to yours. The earlier GP's were slightly different.

You probably have a 231 V6 (Buick sourced) so the trans will bolt up to the engine. That trans is likely a 200 R4. It will work okay behind the 400 engine but enthusiastic throttle use will turn the trans into Rice Krispies.

The engine mount bolt pattern with your 400 may be 2 bolt or 3 bolt (not sure).......some mods may be required if its the older 2 bolt........the 301 was a 3 bolt style.

There may be additional details that someone else may be able to provide.

[MrPbody]

Magicrat,
Unfortunately, the 301 stuff isn't REALLY the same as the 400. It LOOKS like it, but the mounting shells are in a different location, and the exhaust is completely incompatible (higher deck on the "real" Pontiacs).

Indian Adventures (Foxboro, Mass.) has headers and mounts for the G-body and Pontiac engine.

The TH200-4R is the better of the OD automatics. It requires upgrades to the planetary gearsets and the sun gear/shell to have a fighting chance of life behind a high torque engine. Level 10 makes a nice one! If you can't spring for a high-end OD unit, go for a TH400 and live with the lack of overdrive.

The '74 400 block has all 5 mounting holes, making it suitable for either configuration.

Jim

[MagicRat]

I stand corrected.

[785cole]

thanks guys. much appreciated