how much horsepower can a

400 chevy small block handle without spliting. with girdle

[Red Rocket]

I get nervous above 625-650 HP and or 7000 RPM. That's at .030 over and below 14:1 compression.

Learned my lesson years ago with OEM 400 blocks- split valleys, broken cylinders, split main webs, etc. All "prime" 2 bolt blocks too.

That's my opinion.

[UL_LUZ98]

so a 10.4 comp 665 horse plus 150 shot does not last long??
thanks steve

[Red Rocket]

Good luck....


You should be OK for a while, some guys have great luck with OEM blocks. Cylinder pressure shortens the fuse it seems.

Your results may vary!! :rotfl:

[MR.hp]

I have had mine together for 10 years now used about 6 out of the 10 regularly but it dynoed at 602hp. So far holding together and it's a 12.5 comp. engine
I know of 2 people that have 10.5 comp. engines with 150 shots and have not had any problems.
I might be building another for next spring as I am taking one out of my other street car to put in my 409.

[Grr]

i know of a handful on turbomustangs.com that are pushing 900hp on stock 400 blocks and they are lasting just fine. I would rather spend the 1500 on a little M block than machine a 400 for over 700hp though.