I would rather have a set of RHS X-heads and do a lil, and I mean a lil work to them than have a chevy with these aluminum lQ9,L92 or whatever they are with their supposed interchangeability with old 350's.fwiw
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I don't think there is ANY interchangability between the "old" small block Chevy parts and the newer LS/LQ series engines.
In fact, I'm sure of it. The old 350 had 5 head bolts per cylinder; the new one has 4, plus, the valve sequence in the head is totally different
(old: e-i-i-e-e-i-i-e; new e-i-e-i-e-i-e-i) so, even though they are both built on 4.4" bore centers, nothing fits.
There IS a company that has successfully grafted the new LS heads onto an old 350 SBC, but it took an act of Congress, and three men, and a boy, to get it done... and, who cares, anyway?