ButchB

iTrader: (5)

I have a stock bore 5.3 and looking for a set of heads to go on it. its a turbo engine on methanol. Seems like not alot of options for the small bore size. Whats the biggest valve sizes that will work? I'd like to go aftermarket casting to get the thicker deck, but i'm also curious whats the max hp made on stock castings.

JoeNova

243/799 heads are the best flowing but highest compression cathedral port heads.

If you're going aftermarket, MAST sells their Black label small bore LS3 heads.

LS1NOVA

iTrader: (12)

Im using Trick Flow 220 as casts on my 3.80 bore 5.3. Had 799's on it but was pushing water at 28psi and 950whp.

mrstepheneades

What turbo are you running?

1FastBrick

iTrader: (16)

WCCH sells a re-worked Edelbrock casting designed to work around the 4.8/5.3 bore.

Trick flow has GenX 205 heads designed to work specifically on that bore as well.

It sounds like your going all out with a turbo and methanol so you could probably step up to a larger head with larger valves. I don't think your going to be able to go past a 2.02 intake and a 1.600 exhaust valve with a 3.780 bore. Since your forced induction I don't think you will have to worry about valve shrouding and air stalling like an NA build would.

LS1NOVA

iTrader: (12)

Had a Precision PT88 on it but just switched to a pair of Turbonetics 6668's.

slowride

iTrader: (3)

Nate, what headstuds were/are you running and did the trickflow heads solve the problem? I wonder what the best 4 bolt block can get away with when using a small bore, 1/2" or 2000, etc headstuds and aftermarket thick deck heads.

LilJohn

The Trickflow As cast 220 will fit on a 5.3 bore with the 2.040 intake valve. Have a customer using these heads on a twin 7668'd 5.3 and the head stays put with 34 psi of boost and enough cylinder pressure to make 1200+ at the tire based on the fuel consumption numbers. He uses the regular ARP head studs with LS9 gaskets.

ButchB

iTrader: (5)

Thanks guys! Right now I have the stock 862 heads with no port work only LS1 intake valves and they are doing much better than I thought they would but I'm ready to turn it up a little more.

10secZ28

iTrader: (6)

Those 862s will surprise you, they can make a good bit of steam.