people get better flow numbers (pre-porting) with the stock ports in the iron headsLT1 Aluminum heads are certainly lighter than the Iron. Are there more disadvantages to using LT1 Iron heads? I wonder about valve size, port shape and all that. Can the Iron heads produce the same power as the Aluminum?
they are both good heads. two different strategies.
aluminum: take advantage of consistent combustion chamber temperature. the reverse flow cooling of the LT1 with the aluminum heads does a really good job of that. the heads have higher compression. also take advantage of the optispark having a good amount of precision (for its time), and run timing advance up fairly high without blowing it up even on mediocre fuel.
iron: usually put in the heavier chassis. hotter combustion, a bit less compression too, which can help with the heavier vehicles hauling big loads. definitely more efficient. you have to run quite a bit less timing or she explodes but make good torque and power anyway
if you're porting them, though, the LT1 aluminum heads are great on a budget. look what lloyd elliot used to do to his LE3 series ports. guys were getting 450+hp crank horsepower out of those heads with a good cam. pretty amazing for ground down stock castings.
in practice, though, your two bolt main block doesn't have any issues until you start generating monstrous torque. i have no idea why they bothered with four bolt mains in the 'vette. very much overkill. some good bearings with some arp bolts so nothing goes stretchy can be reliable well over 500hpOther disadvantage of this setup is that it is a 2bolt main block.
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