Originally Posted by zipper06

They can probably handle around 600 HP. i have 2 of them a 4 bolt and a 2 bolt that's in my car now on alcohol. I don't know how much HP it has but it runs 6.50's in my 3250lb Malibu with a toilet bowl, got 200/300 passes on it.
One thing you must absolutly do is put 1/8" pipe plugs in the water holes to keep it from breaking /cracking between the head bolts i also plug the steam holes.you should also run head studs not bolts. I've ran them for 25 yrs. and the biggest problem i have had was not preparing the block deck properly. With that said i've also cracked cylinders on blocks that the casting bores was was not centered, so it's a good idea to have the block exrayed to determine the wall thickness and have the bores shifted to made the cylinder wall's more equal.

JMO

Zip.