js2fst

iTrader: (12)

I have ported 317's ls9 headgaskets how boost of hp can I do is take

js2fst

iTrader: (12)

Also studs and it is a lq4 iron bloc 408

Wicked69

Probably will take more than you need. 20lbs shouldn't be an issue with studs and LS9 gaskets.

js2fst

iTrader: (12)

What else to prevent it

typhoon1015

iTrader: (5)

a proper tune and good fuel it will live decently depending on goals

and your first post is a bit confusing,
"how boost of hp can I do is take" lol

MillsMotorvation

With studs, any psi, stock 6.0 bottom end 10psi.

allout06

iTrader: (11)

ill reiterate what AES told me. from their testing, they see the 6.0L iron blocks start to push water around the 22.5psi mark on a 4-bolt head, standard head stud. They said the heads lift a little, but from what theyve seen, its more so the cylinder walls themselves expanding about the width of a human hair, and causes water to enter the cylinder. take it for what its worth.

Old Geezer

iTrader: (3)

too many hits on the bong, while typing!

stock48

iTrader: (17)

Stock bottom end Lq4 with 317 heads with ls9's, and std ARP studs and S480 Maxed out at 25 psi no water pushed. Can't say how long it will hold with 25psi but been many pulls with 20~23 psi. Different blocks and heads are thicker than others so hard to put an exact number on it but if things are right you should be able to run 20~23 psi with no problems. The 2004 up blocks with short head bolt hold better than the early long bolt blocks. With early block, and std MLS(pre ls9) gaskets I started to push water past 20 psi. Also deck prep/surface has a lot to do with things, those scotchbrite discs many people use destroy decks.