Cast crankshaft OK?
#22
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From: Frankfort IL
I'm planning on either the Hi-Tek exhaust, or the Barr replacement center rise manifolds from an 86 up Chrysler marine engine with adapters to use Mercruiser risers. If I went that way I'd use some extended stainless risers. I'm a little concerned with the bare 2-3" of pipe on the Hi Tek manifolds but they are the only other option.
#23
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While I agree a wider LSA is typically desired, there are other cam specs that come into play. The STOCK cam on a gazillion Merc small blocks and ski boat small blocks came with 109 LSA (GM "395" cam). So just looking at LSA is one factor, but not necessarily the deciding factor regarding reversion.
#25
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From: Tampa, FL
I had those on my 390 stroker...... keep in mind you can use regular(cheap) small block chevy roller rockers on the magnum heads.... just get the right studs....... I would say you don't need much cam to get 450Hp from a nicely built 408..... 900HP in your boat will be crazy as it is.... I would say keep the cam mild on duration and minimize the reversion chance.......... TBF
#26
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From: Frankfort IL
I had those on my 390 stroker...... keep in mind you can use regular(cheap) small block chevy roller rockers on the magnum heads.... just get the right studs....... I would say you don't need much cam to get 450Hp from a nicely built 408..... 900HP in your boat will be crazy as it is.... I would say keep the cam mild on duration and minimize the reversion chance.......... TBF




