i would think if u need 900 hp out of a small block blown engine..either aluminum or iron block will work...i had a small block alcohol blown injected engine at one time....i heard rumors something close to what dcarr was saying in that the aluminum would give to a certain degree (heat/cold)therefore making it a little more tricky for sealing up the HEADS TO BLOCK ...but you have to keep in mind that when this was mentioned the blower was gonna pack 22-25lbs of boost into the cylinders.
i assume your boat will be for recreational uses,,being that it will not endure the thrashing a all out race motor will see....plus if the boost stays 10lbs or under you are not gonna face the problem with squeezing out head gaskets etc..if it were not o-ringed to begin with..
i have heard nothing of the fact about mains giving up in a aluminum block no more than a iron block...i am with the other guys..the man is telling you something that does have some merit to it but maybe doesn't apply in your case......
NOW I WILL SAY THIS...it is highly recommended that aluminum rods be used in a blown or NOS motor..for the fact the aluminum rod will cushsion the impact that will reach your bearings....SO i WILL agree that you will stand a chance of changing out your bearings sooner with a steel rod over a aluminum Rod..
Maybe thats what your seller has heard and getting it confused with the mains ????? :roll: :roll:
thanks brian
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Bjuice..
"I'M YOUR HUCKLEBERRY ! "