Fuel Injection and new engine

[Dudeman]

I've got a '75 Jimmy with a 400 in it. The engine is REALLY tired, with about 230K on it. I bought a fuel injection setup off a friend, who had it on a '57 Chevy w/ a 400 (he replaced it w/ a big block). Do you guys think I should rebuild my existing motor, or get a crate 350 or 383? I'm worried about the setup on the FI computer. It was setup for the 400, so will different CI screw it up?

 

[Mad-Dog]

I wouldn't rebuild the 400, that block has siamesed cylinders (no water jacket between the bores) and suffers from cooling problems.
Build a 350, 383 or 391, the 391 build uses more stroke than a 400 is a torque monster but it has a very low rod ratio and redlines around 4500.
A 383 with 5.7" rods will make roughly 35 more ft lbs of torque than a similar 350 but will redline at 5500.
Decisions.....decisions

Oh....BTW, the F.I. should work fine with either the 383 or 391 but may be a tad rich on the 350 and require calibration.

 

[MikeS]

Do a fresh 350 or 383. It's a pretty simple fix to just have the computer chip reprogrammed to match your engine. There are lots of places that will do it. Even it you were building a 400, you'd probably want to do it anyway so it matches your cam, gear ratio, tire size, etc.

Mike

 

[Dudeman]

Funny you say that. I used to have a '73 with a 350 and I had serious heat problems with it. I bought this Jimmy in Sacramento, CA, drove it in the summer as a DD and never had a problem.

Guess I was freakin' lucky.