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What heads to go on my stroker LS1?

This is a discussion on What heads to go on my stroker LS1? within the Internal Engine forums, part of the LSx Technical Help Section category; Hi Guys, new here. I have a TVR with a stroked LS1, a few days ago i bust a valve ...

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    What heads to go on my stroker LS1?

    Hi Guys, new here. I have a TVR with a stroked LS1, a few days ago i bust a valve spring. I have early ported heads on at the moment, so was thinking to upgrade as its all off. The Livernois heads look good value anyone had any dealings with these? Also while i'm here i run a Comp 275 with 1.85 rockers and it looks as though i have just been touching the valve/piston, would a thicker head gasket with smaller combustion chambers be possible? The change of top end power was dramatic when i put these in so would prefer to keep them. Cheers.

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    I Like It Stroked 99Ls1fever's Avatar
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    1999 Z28 408 Stroker M6

    Quote Originally Posted by lstvr View Post
    Hi Guys, new here. I have a TVR with a stroked LS1, a few days ago i bust a valve spring. I have early ported heads on at the moment, so was thinking to upgrade as its all off. The Livernois heads look good value anyone had any dealings with these? Also while i'm here i run a Comp 275 with 1.85 rockers and it looks as though i have just been touching the valve/piston, would a thicker head gasket with smaller combustion chambers be possible? The change of top end power was dramatic when i put these in so would prefer to keep them. Cheers.
    what type of stroker 383? 402? I would say at least 2.02 and up to 2.25's but we need to know your motor first.

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    it would have been nice to to tell us what cid the motor is......
    here's a general guide that'll get ya close
    350cid-180cc intake runners
    383cid or hot 350cid-200cc intake runners
    402cid or hot 383cid-220cc intake runners

    ya gotta be careful when selecting heads because too large of a intake runner will kill the bottom-end, while too small of a intake runner will kill the top-end

    If the valves kissed the pistons at all then the valves are bent, i don't care how slight you think it was, the valves are bent....

    Increasing head gasket thickness will fix one problem and create another...
    the problem is your rocker ratio is too high for the selected cam, so you wanna increase head gasket thickness to alleviate the problem......ok.

    the thicker gasket will cause the motor to lose static compression and increase squish band making the motor more susceptible to detonation and pre-ignition...
    but the good news is that the valves wont hit the pistons anymore, you hope.

    When the rocker ratio is increased the effective valve lift is increased, cam grinders are very specific about which cams enjoy high-ratio rockers and which cams don't.....they dont want your valves to hit the pistons so they say "dont use high-ratio rockers with certain cams because the valves may hit the pistons".

    FYI: the correct technique to cure the valve/piston issue if you insist on using high-ratio rockers with that cam would be to notch the pistons

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    Hi Guys, thanks for the advice, its a 383, i've gone for Dart 225's in the end from AMS racing. I measured the deck to valve on the old heads and that was around 3.7-3.9 mm, so AMS have cut the valves slightly so am just over 4.5mm now, so this should sort the valve clearance. The Dart heads have a 62cm chamber and we have cc'd the old ones at 68cc so the comp ratio should be up a bit! We do have 98oct fuel over here so detonation wont be a problem, and i can always back a bit of ignition as my ECU is fully mappable, i have an LS2 inlet manifold and a 90mm TB also. Any more advice is welcome though!

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