Do NOT use the iron heads you need to get the 317 casting aluminum heads the iron heads dont dissipate heat nearly as well and dont flow as good either thats why it was so cheap tell them to keep the heads and find you some 317s. 99s have the longer crank snout but you are going with a stroker crank so that doesnt matter.

 

What about the heads off of his 4.8?

 

You can use those but they dont flow as well and have a smaller combustion chamber so you will most likely have to go with custom pistons to get the right CR. I had to get my pistons custom made by JE to get the correct CR for my setup so that later on down the road I could put a set of 6L heads on and drop the copression enough to put FI on it but have ~10.7:1 CR right now. You really need to get a CR calculator and talk to a reputable builder to get all teh numbers right. The LS1 series cranks have a big reluctor to clear and and also you ahve to figure if you are going to have th pistons in the hole or out there are way too many variables to go through right now to make sure you get the setup right. Going with a set of 317 6L heads would be the best way IMO.

 

Nuff said.

 

I can put you in contact with someone that can get you the stuff cheap and also do all the figuring for you

 

I always thought the aluminum blocks could go bigger because of the sleeves that you can change?

 

You only hav eso much room to work with and if oyu are going to spray a bunch of nitrous or have an FI motor IMO its better to go with an iron block cause inherently stronger than an aluminum block but heavier. Alot of the f-body guys use the iron block fo rtheir 408 builds due to the strength too.