Alluminum Or Cast Heads Pros & Cons
01-23-2003, 01:28 PM
#11
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I was told that you could run about a pound more boost thru Aluminum heads and not worry about that "D" thing. 
BTW...Whats the static CR and size carbs on that 10-71/572?
BTW...Whats the static CR and size carbs on that 10-71/572?
Last edited by Back4More; 01-23-2003 at 01:31 PM.
01-23-2003, 01:36 PM
#12
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That "D" thing is very important, but you can run more boost with aluminum. I did 2 otherwise identical 565's a while back to prove the point. Same Littlefield, cams, compression, heads,..........
One had "D" pistons, the other round depressions. It took 2# more on the round dish to equal the "D". In the boat, the "D" uses less gas, even with the same boost. Turbulence in the combustion chamber is the reason. You must also have about .040" deck total, including the gasket for best performance.
Those particular engines made 1,007hp and 1,006hp at 9 and 11psi, 6,200rpm.
One had "D" pistons, the other round depressions. It took 2# more on the round dish to equal the "D". In the boat, the "D" uses less gas, even with the same boost. Turbulence in the combustion chamber is the reason. You must also have about .040" deck total, including the gasket for best performance.
Those particular engines made 1,007hp and 1,006hp at 9 and 11psi, 6,200rpm.
01-23-2003, 09:14 PM
#15
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Aluminum heads flow better than cast...period.... There is no way you can get a cast head to perform like a aluminum head...if you can please let me know and I will notify every race team crew chief with the NEW CAST PERFORMANCE info!!!! I gained huge horsepower on my 572 with aluminum heads!!
01-23-2003, 09:25 PM
#16
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Fountainracin42,
You can get aluminum in more configurations than iron. If really big ports is what you need, there are no comparable irons available.
If you need a head that is of comparable port volume to an aluminum head, the facts stated above are factual. Any good porter can make a well designed iron head flow about the same as a comparable aluminum one. He might not like the time needed or the iron filings, but it is commonly done. Ask some good porters. JimV maybe? Try calling World Products. They make iron and aluminum versions of some BBC heads.
You can get aluminum in more configurations than iron. If really big ports is what you need, there are no comparable irons available.
If you need a head that is of comparable port volume to an aluminum head, the facts stated above are factual. Any good porter can make a well designed iron head flow about the same as a comparable aluminum one. He might not like the time needed or the iron filings, but it is commonly done. Ask some good porters. JimV maybe? Try calling World Products. They make iron and aluminum versions of some BBC heads.
01-24-2003, 11:30 AM
#18
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It's not so much the matieral it's the patterns. For example World Products have not changed their patterns in years on the iron heads. The bowls are shallow in the exhaust and intake ports. The later pro one heads have better ports flowing more air out of the box because of design. Also the aluminum heads are thicker allowing more room for porting. As far as the difference in one being more smooth than the other, (or parasitic drag) accounts for only two percent max air flow loss on lets say the wall or floor of a port. The rules change at the turns and near the seats.
Last edited by JimV; 01-24-2003 at 11:32 AM.
