need help with big block heads

[newschool]

Thanks for all the help - this is my first big block to build and I'm finding out that they are alot more expensive and harder to find parts for around here (West TN). Is it true that I'll need a 119cc combustion chamber since I am running the 11:1 dome top pistons - to have enough clearance so the valves and pistons don't hit? Which BB heads were better - the oval or the rectangle ports? I really appreciate everyones help - I'm trying to get a grasp on all the BB Head info. I would love to buy a new set of aluminum heads - but I have a baby due in Feb and a couple other car projects going, so I'm tryin to watch my funds, especially since this is not a car I'm going to sell.

[Efi69Cam]

Originally Posted by 3kidsnotime

Gen 5 and 6 heads are the same, the diff between a gen 5 is a non roller engine in 96 the engine was changed to a roller engine with raised lifter bores and noted by a composite 6 bolt cover the heads are the same casting number the crank rods pistons are as well, both 5 and 6 are priority main oiling gen 5 and 6 use the same head gasket 4 does not If it is any need I can snap some pics of 5 and 6 heads I have about 45 take off sets, do your research its your money. That is based on production gm iron heads, If you take the gm performance aluminum heads the new ones they will work on all blocks except gen 7 8.1 series, those heads as all ne aftermarket alum bbc heads have small water passages but added material to seal the block on 5 and 6 motors if using them use the correct head gasket.

http://www.sdpc2000.com/faq/kbhowto.asp?mt_node=360
Some interesting reading for you.

The blocks might take the same gasket but the water holes in the gen 6 deck are smaller, and thus the mark 4 heads work.