Hey, I need some help picking the right cam for my build. So basically what I have is a stock 5.3l engine that I�m putting 317 heads that are milled .030.. what cam will be the best for max Hp for my build. If you have any other questions just let me know and I�ll try my best to answer ASAP!

 

Which car, what sort of use, street, race, or both?

 

it�s a 2004 GMC Sierra single cab and also street/race more the race side lol

 

Are you going with forced induction later? What's the purpose of going to a 317 head???

 

I read that the 317 are the same port design as the 243 and 799 so I got those and had them milled and I�ll probably spray it or turbo it down the line..the 243 were just way to hard to find for a decent price

 

A standard 5.3L with 706/862 heads is around 9.5:1 compression.
A standard 706/862 head is 61CC
A standard 317 Head is about 71CC

Even if you milled them enough to achieve 65CC you would be just below 9:1 compression...

I really wouldnt worry about port shape or overpaying for 243/799 heads. You can achieve the similar flow numbers from a 706/862 head by increasing the intake valve. They have a small 1.89 valve. You can install a 2 inch valve and open the throat up when doing a valve job.

 

You might not want to go bigger than 1.95 on the intakes in a 5.3 to avoid shrouding the valves. WCCH uses that when doing 706/862 heads for 5.3's for that reason.

 

WCCH Put 2.00 valves in my last set and GM used the 243's with a 2 inch in the GMT900's so it must not be that big of an issue.

But MAMO did a custom set of heads for me with 1.95 in them for a 5.3L... Just waiting on Dyno...

 

I bet GM did it because they work pretty well in spite of any shrouding issues, flowing well enough for the trucks they were in.

 

stick with the 706/862 heads