[garye]

As to your 400 SBC

Achieving 500 HP is possible but longevity is medium at best

Recommend start with '70 to 72 4BM blocks

Have built several "street" 400's

Some 2BM's but really recommend the 4BM block

Getting hard to find as they only used 4BM for those above years

4 BM had inherent weak points in center 3 main webs

If using laughing gas or boost or planning to twist this engine

past 5500, recommend lower end studs and billet caps

Have one of my 500 (yes, actual 501 HP Dyno'ed) 400 + 30 engines

in a '78 Malibu and it runs great

Not really that radical

Has AC!

Hope this helps-more info if needed

[vinniekq2]

Is your question how to make 500 hp or how to make a 400 cu in engine reliable? If its just power,then what the fella said about AFRs dyno page.Get a set of good heads that flow 270 cfm,good manifold,carb or compatable efi,moderate hydraulic roller cam,1 3/4 inch headers,10 ish:1 static CR.Full balance and blue print of engine,good parts for reliability.Studs are a good investment,longer rods are better than stock,forged crank is a good idea. 1.2 horse power per cubic inch is still very street friendly.I would use an open plenum intake manifold,,,

[Greg T]

Use flat top pistons @ zero deck, a set of Etec 200 heads or equivelent, an Ede 2201 roller cam and lifers, an RPM Air Gap manifold and a highly tuned 680 to 750 cfm QFT carb. Limit advance curve to 16*, set initial at 20*, 36* total at 3000 rpm, add 10* of vacuum advance plugged into full manifold vacuum and enjoy about 480 hp and about 510 lb/ft of torque with gorgeous streetability. BTW, peak power is all in at about 5800 rpm.

[hcmengines]

You can build a better engine, a 383. I can tell you how.
The other advice, well to much compression is the enemy with a 400
from there 5.7 rods and other things will make an OK engine.
Have good caps put on a 2 bolt, 400$ min.
but, 305s and 400s are junk for the most part. Dont go more than .020
over if you can help it, siamese cylinders with little material for the head gasket, I could go on but some 400 lover will tell me Im wrong.