Hello,
Does anyone know how much horsepower a cast bottom end will hold up to?
I am planning on either a 355 or a 383 with AFR heads, and the pistons will be forged.
If I would ever use any nitrous it would only be a 125 shot.
If forged is a must I will wait a little longer and do it, but it would be a lot sooner if I could use cast or even a used steel crank.
Thanks in advance.
Steve.

i think it's more important that everything is balanced instead of bulletproof at the power level you want.
my 355 has a stock cast crank, PM rods, and lightweight forged TRW pistons- all balanced- and is allegedly good for 400 or so horses, and it has seen the high side of 7000 rpm's on a few occasions. my machinist- a guy that builds winning engines for roundy round guys in claimer classes- said i should have zero worries for a long, long time with what i've got and what it is used for. don't know about the nitrous, tho. never asked about that. couldn't hurt to have stronger parts, but might not be strictly necessary.

almost forgot- i am running ARP main studs in my 2 bolt block, and it was align honed. when i put it together and gave the crank a spin after torquing the studs down, it just kept spinning. zero friction is also a good thing. 3 summers and 20,000+ miles is a pretty good testament to the durability of stock bottom end parts, if properly set up.