In my local paper an ad just ran for a 400 SB at $750. I called on it tonight and the guy I talked to turned out to be an engine builder, not professionally, but he builds for people on the side. He gave me plenty of advice which I was glad to hear.
As it turns out the motor was originally out of a '77 Blazer. It has been reworked and this guy used it in one of his cars. It has a fairly mild cam and setup as it was a daily driver. He estimated it was between 380 and 400 horses with almost the same torque. My car is a '90 Formula with a 305 TBI.
Do you think I should pursue this motor. The guy I talked with said that it would be a fairly easy swap and that with TBI I could just put a regulator at the carb and keep the same fuel system. He also seemed to think the 700r4 would handle the motor. Is this all true in you experiences? Has anyone else succesfully put an older 400 in your third gen?
Also, if I were to up the compression and put a better cam in to up the power to about 450 (hopefully) will my tranny handle it?
Please tell me your impressions of this whole story and give me any and all advice you can. Thanks a lot.

I cant condemn the entire species of the 400 SB, for im sure i just had the outright unlucky truck of the bunch... But i ahd a 1985 k10 4x4 with a 400 SB in it, and the damn engine was garbage from the moment i got it. Originated in the same place, from a 76 blazer. I had it backed by a th350 tranny. Problem #1: 6 miles to the gallon. Yes. i said six. Problem #2: while i wouldnt doubt what this guy is telling you, everything ive read about them says they are torque MONSTERS, but not great on HP. This was definetely the case in my sitch.... It launched off the line, TONS of brute strentgh, but not lots of HP. The engine eventually met its match on the highway, when a bearing shattered, leaving the cam to fly around the block for ten seconds, shredding the innards of that engine to scrap metal shavings, which was all that fell out when we dropped the oil pan afterwards.... hehehe. I love my thridgen.

------------------
1988 Formula, 305TPI, 700r4(for now), headers, stage 2 PROM, modded MAF, cat back, no catalytics, cowl hood, centerline champ 500 rims, KOBEL predator ground effects kit, Trans AM tailights, dash pouch, 92 shift console w/indicator, white face gauges, accented red trim, 12 speaker stereo, 4 amps, tint, T tops... icq 44373460 AIM:admrlam
see it at www.geocities.com/admrlam/bird.html

Look for early-model 400" blocks. Good starting point is 1971-1972 Monte Carlos. Look for the following criteria:
1) 2-bolt block. 4-bolt caps too close to cylinder walls.
2) 2 freeze plugs on side of block. These blocks have higher nickle content and are stronger.
3) Find one with stock bore. More than .030" over and you'll have troubles.
4) Always pressure-test block before building. Cracks are popular in lifter valley and coolant passages.

------------------
1989 Formula, 383", DFI, Mini-Ram, S-Trim Vortech, blah, blah...
Best ET: 10.796 @ 125.8 mph

TURBO 406 PROJECT STARTED!!!

Other expensive hobby: assault weapons/shooting sports

Employed at:
Hahn Racecraft
Accel EMIC/DFI Tuning
Turbosystems & Custom EFI

Member of Midwest F-Body Association
http://www.mfba.org

An older 700r4 pre 87/88 will not handle that torgue. At the least plan on some clutch mods.