one fast zo6

iTrader: (490)

hi will a 243 zo6 head work on a 5.3 trunk motor/ will the valves clear the small bore?
thanx thomas.

ss.slp.ls1

iTrader: (36)

+1, It will work fine. You may want to mill down the heads because the increase air flow might be negated by the CR drop. Don't know how much to mill it though, maybe someone will chime in or I would contact a machine shop that knows LSx motors and ask them.

Shawn MacAnanny

iTrader: (12)

The 07+ 5.3Ls all get 243s. And they have the 2.00 1.55 exhaust valves.

one fast zo6

iTrader: (490)

thanx keep the info coming! what type of power can you make with it!

ss.slp.ls1

iTrader: (36)

With modding the 5.3 in general, or just from the head swap alone? If you mill the heads so that there was no drop in CR, I'd say you could expect 15 rwhp.

I would hope that you are going to be changing the cam at the same time you are changing your heads.

one fast zo6

iTrader: (490)

yes i have a GM hot cam, zo6 valve springs, rollmaster dual roller timing chain and want to mill the heads .025. i hope it will make 330 rwp

stumprrp

iTrader: (2)

should make more then that man!

Taubr Unit

iTrader: (32)

Im putting a set of 241s on my 5.3 but im boosting it so the lower compression will help me out some.

ss.slp.ls1

iTrader: (36)

Sell the 241's and pick up some 317's. It will flow more and drop your CR more. Also pick yourself up a LS6 cam. It is a very good budget boost cam. Doing those things will allow you to run more boost safely...and make more power.

Taubr Unit

iTrader: (32)

well i already got the 241s with only 20k on them for $50, cant pass that up, and i plan on getting a cam, just a little bigger then the z06 cam. Thanks for the suggestion thou!

ss.slp.ls1

iTrader: (36)

I'd still sell them and get the 317's. It's a much better choice. Ask the boosted guys, they'll tell you. You can pick up a set for $250 or less.

Taubr Unit

iTrader: (32)

not tryin to hijack ure thread but i did sell the 241 heads and picked up a set of 317s, lol. Should put a 5.3 around 8.5-1 comp.