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Old 01-25-2010, 07:05 PM
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Hey Trb

Hey Man, Sounds like you've got a serious project going on now. I've been to busy too post some info for you. But I have it now. Sounds like you have a 454 that may have been assembled with a grab bag of parts(not uncommon w/marine engine builders). They used whatever GM had available that suited their needs. I don't know if a rebuild is in your plans, but its going to be hard to determine just what you have without a complete teardown. Here is what I found in my books; While the pistons and heads make it appear to be an LS6 engine, the block and intake say it isn't. Your block appears to be a later light duty truck block(14015445)produced~'75-'90. LS6 is 3963569. Your heads are the LS6 real McCoy(6272990)('71 open chamber)(probably old style valve seats,not hardened). The LS6 heads with hardened seats is the 14096188. Your intake is from '68-'69 396/427(3933163). LS6 intake is 3963512. Your pistons are the early closed chamber LS6 design, because they are std. bore, it makes me think it was a purpose built engine. Also drops the compression about a point using the closed chamber piston with open chamber heads. L2349 specs; 10:1 with 119cc heads,.265 dome, 5/64,5/64,3/16 rings,press fit pins,4.25 bore,comp. dist 1.645,658 grams weight, dome volume 30.6, bore clearance .004. As far as the cam is concerned, you may want to pull the original and see whats in there before deciding on where you want to go. From my experiences with boat cams, don't get too greedy with the duration, use generous lift(check piston to valve clearance) Use a wide LSA for idle quality. If it were me, I'd have the original reground to whatever you want, because it gonna be a special order anyway, you'd just as soon save the cost of the reverse cam blank and only pay for a repair/regrind. Hope the info helps. olnolan
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