Small blocks and HP

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Post from: Steven Parker (dragon64 at ntcnet.ntcnet.com)
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According to several sources (none which completely agree) the 2-bolt blocks
with ARP main studs should safely handle around 550hp, 400hp with bolts.  An
OEM 4-bolt block with bolts should handle around 475hp, 700hp with ARP main
studs.  And OEM block with splayed 4-bolt should handle over 950hp, and a
Bowtie Block with the splayed 4-bolt should handle 1500+hp.

Sources include books, mags and Gorden's machine shop and Jim Oddy's Dyno
Service in Elma, NY.  In most cases I went with the lower values and rounded
off to be on the safe side.

So essentially, a 2-bolt block w/ studs should handle anything a normally
aspirated small block can produce.  (assuming everything is in good shape
and tolerances are closely followed)

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Post from: Steven Parker (dragon64 at ntcnet.com)
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        Recently I had posted info I had dug up on power level that various
blocks and main-caps should be able to handle.  I have since learned that
engine RPM plays a larger factor in determining safe power limits for
various block/cap combos.

OEM 2-bolt blocks are good to 6000 rpm.
2-bolts with ARP studs are good to 7000 rpm.
OEM 4-bolt blocks are good to 7200 rpm.
4-bolts with ARP studs are good up to 8500 rpm.
Bowtie or OEM 4-bolt Splayed Studs and cap are good for well over 8500 rpm.

-These figures were taken from a Super Chevy magazine at work.

In the Article, it stated that a 250hp engine that was spinning at 7500rpm
exerted more loading force on the Main-caps than a 550hp engine spinning at
only 5500 rpm.  This means power and RPM must be considered when selecting
how much beef you need in your bottom end.

The HP figures are good references, but the RPM limit of the motor is a
better way to choose your block according to the authors of the article.