SingleCabSierra

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知 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値l try my best to answer ASAP!

G Atsma

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

SingleCabSierra

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

1FastBrick

iTrader: (16)

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

SingleCabSierra

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値l probably spray it or turbo it down the line..the 243 were just way to hard to find for a decent price

1FastBrick

iTrader: (16)

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.

G Atsma

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.

1FastBrick

iTrader: (16)

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...

G Atsma

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.

Ls7colorado

iTrader: (3)

stick with the 706/862 heads