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?

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.

Is that considered the "quench height" I read about but never understood?

Yep!!
Back4More, that is correct. If you can get one, the Keith Black Pistons catalogue has some great info on this and several other topics. If you can't find one, post or pm and I'll try to show this part.

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!!

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.

Fountainracin42
Thanks for your input I appritiate it. I am calling them today to give my engine colours and find out whose heads he is using

be cool

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.

THANKS JIMV
THATS BASICLY WHAT THEY ARE TELLING ME THE ALLUMINUM IS PORTED BETTER AND POLLISHED CLEANER THAN THE STOCK CAST UNITS