What exactly is a 351 modified 400 engine? My friend has one from a late 70's pick up, was thinking about using it in a 86 foxbody if it is something worth using. What tranny would bolt up to it?
A 400 could potentially be a pretty sweet engine, but it will cost quite a bit of money to get it makin a lot of power and it has the big block bell housing bolt pattern. If you're into 335 series engines you'd be best of sticking with a 351 cleveland.
Unless it's a fresh motor or is already beefed up, I would probably stay away from it. I think you would be looking at alot of weight, lacking on power, and custom headers just to name a few. Now if you had an old pickup, that's a different story. The 400's made great torque and low RPM power, but you can't really spin them up real fast.
You would need a big block bell C-6 or an old cast iron 4-speed as far as trans.