I have found a set of 6.0 LQ9 #317 heads, and was wondering if they would fit my 2002 silverado 5.3 and if so would there be a horsepower gain...
Printable View
I have found a set of 6.0 LQ9 #317 heads, and was wondering if they would fit my 2002 silverado 5.3 and if so would there be a horsepower gain...
They will interchange without any problems. The heads have the same flow characteristics as the LS6 head. BTW, 317 heads are LQ4 low HP heads, not LQ9. You will lose compression with the 317 or 035 LQ9 heads on your truck. you either have 852 or 706 heads with 61.15cc chamber volume and the 317/035 has 71.06cc chamber volume.
I have two different manuals on LSx engines. Will Handzel's book says the 317 head casting was used on both the LQ4 and LQ9 engines. Chevy LS1/LS6 Performance by HPBooks make no mention of the 317 casting on the LQ9. Food for thought.
How much Estimated HP would you think, are they worth $300.00
Nope, not worth it. THey'd be great if you were going boosted and needed to lower your compression. BTW, updated my reply.
thanks man, so you think it will hurt my truck more than helping it?
I think it will hurt your performance until you get boosted. I'd buy a set of long tube headers, a cold air intake, Nelson tune, polish the throttle body, a 3200 rpm stall, LS6 cam or add a limited slip diff instead.
Yeah i am sticking with my stock heads because I dont intend on adding a turbo or charger. I think I will just get them ported and polished and get some ASM long tubes and a 2800 stall. I had a chance to get some 6.0 heads also but passed for the same reasons as said above.
Chris
Don't forget the valve size is too large for the bore... 2" intake on a 3.78" bore will shroud it, kill velocity, reducing your already minimal torque.
Keep your heads.
sounds like a tune would do the most for the least. That sounds like a great engine for about 8 lbs of boost.