3.9" Bore LS7 heads
3.9" Bore LS7 heads Anyone running these yet? Ive been drooling over them for a couple weeks now
http://www.racingheadservice.com/rhs...r-ls1-ls2html/
http://www.racingheadservice.com/rhs...r-ls1-ls2html/
Those valves are enormous for 3.9" bore. While I love LS7 heads, they give up midrange vs cathedral port on 427 combos (but make a lot more HP). On a 346 or 383 it'd be interesting to see...
intake valves would need to be a tad smaller in order to not be shrouded in
a 3.9 bore. Just adding those diameters now is 3.865"...leaving only .033"
stock bore or at most .040" with a 3.905". Figuring .015-.020 between the
valves leaves very little room on the chamber sides. For a forced induction
application though they would be pretty insane.
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valves in GM LS3 castings to make them small bore compatible. In that case
you already have a large volume runner and a bowl originally designed for
the 2.165" sized valve. Not exactly ideal.
What would be really cool with these RHS heads is if they took the P-port version and kept it as small as possible (cross sectional area) and perhaps a
volume of 240-250 cc range. Even 2.055/1.6 or 2.08/1.57 combo of valves
when combined with that LS7 runner shape would definitely move some air.
Still got that stroker combo on your mind DR ???
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Verdad Gallardo I thought recently that someone posted a link to a company putting 2.08 IN valves in GM LS3 castings to make them small bore compatible. In that case you already have a large volume runner and a bowl originally designed for the 2.165" sized valve. Not exactly ideal. What would be really cool with these RHS heads is if they took the P-port version and kept it as small as possible (cross sectional area) and perhaps a volume of 240-250 cc range. Even 2.055/1.6 or 2.08/1.57 combo of valves when combined with that LS7 runner shape would definitely move some air. Still got that stroker combo on your mind DR ???
I sold that crank when I picked up the Vette. The Mast small bore LS3's have the 2.08/1.57 combo. I believe it's a 240cc intake runner.
I've always thought about what if someone bought the ballistic speed ls3's and welded the runner up some, making it smaller for a bit more velocity, and using a 2.04/1.6 valve combo.
At that point they'd be the same price as Mast's, but with a hopeful more bit of velocity. I believe someone has welded on the ballistic speeds here lately...
I don't know why AI doesn't offer a ported LS3 based on their highly successful port program. They could just weld up the LS3 chamber and run a much smaller valve 2.055/1.57 combo with the LS3 port work they do and have a beast head for the smaller bores. 62cc LS3 head with much better PtV clearance...
According to the 2014 new products brochure they have 2.10 intake valves and are also available in a P-port version.
http://www.mediafire.com/view/qr98u8.../CPG5-2014.pdf
http://www.mediafire.com/view/qr98u8.../CPG5-2014.pdf
Last edited by badassracing; Dec 4, 2013 at 01:00 PM.
