Hi I have a 5.3 out of a 2000 truck, From what I�ve read I could use 317 heads that would flow better but at the cost of compression. so my question is if I used flat top pistons to raise compression and 317 heads how much compression would that leave me with and what kind of power would I gain, also what would be the best cam for this combo?

 

You would be better off finding some 243/799 heads. Same ports with more compression.

 

Assuming a zero deck, stock 317's and a 0.040 head gasket your about 9.5:1. Now if you take the same setup with some stock 243/799's and your around 10.3:1.

 

I know but 317 heads are cheaper and I don�t know if I wanna go for that compression and require premium fuel

 

what kind of power increase would I see with the higher flowing 317 heads at 9.5 to 1

 

LS engines with 10:1 compression can use regular unleaded fuel. All Gen IV 5.3's have 10:1 and use regular.

 

It would be lazy down low and I think the engine due to the smaller bore would respond much better with 862's or 706's but if your looking for the better of the two then the 243's would be the WTG unless you have plans on throwing boost at this thing. I really don't know how much of a power difference there is between the heads as camshafts play a big role in the engines performance and then there's of course the all mighty boost factor that can be thrown into the mix. What are your plans for the engine and what other changes are you making to the the drive line will dictate which way to go with a camshaft. TSP and Cam Motion can certainly help you choose the right cam for your application.

 

if I was to get some machine work done to my 706 heads say ported and valves plus get my compression around 11.5 to 1 what kind of power could I expect