Hey guys, im looking for opinions on whether to rebuild my 317s or opt for some new GMPP LS3/L92 heads and maybe even go all out and get the CNC'd ones.
I know a lot of people make big power with the 317s, just wondering what the pros and cons are to going to the big LS3 ports and even more so the CNC ones. And yes i know i need to run an LS3 style intake.
My goal is a streetable driver with low 9 capability. Im not putting an overly agressive cam in it, 569 lift, 224 duration, so the way i see it i would benefit from a bigger head to get the air volume at lower lift numbers. Am i wrong to think that?

 

If your using a stock bottom end I would not spend a ton of money on heads, if you blow the motor, you just wasted good money. Just my .02$

 

Velosity trumps volume 317's all the way, just do a home port job on the intakes get that big hump out of the way you'll be happy. Like 496 say's spend your money somewhere eles. Because you said it yourself streetable.

 

I do plan to do rods and pistons, polish the crank and balance the assembly, the engine has 300,000 miles on it lol,

its originally was supposed to be a junkyard build but ive decided to take a bit more time and put some more effort into it and make it a little stronger and durable for the long run. The car is getting AC and a 4l80E to help with the driveability.

The reason I was looking at the LS3 stuff is for what it will cost me to get the 317s milled, new springs, valve job and then port them, I can buy a set of brand new LS3 or L92 heads for $500 each with the right springs ill need.
Wouldn't volume on the intake side create velocity on the exhaust side?

 

Milled $75, competetion valve job $125, port them yourself, springs $150? up to $350 now. Big heads are like big carbs LAZY down low unless on big cubes. If race only go bigger. Why is everyone reducing the size of there exhaust to feed there turbos now? To keep the velosity up. Same apply's on the other side of the valves also. The valves are only open for a short time you need to fill the cylinders quickly. Crisp throttle responce is tops on the street, you will soon not enjoy driving a dog down low engine. Theres a reason why the engineers at GM put 317's on the 6.0's. Spend your money on good turbo parts and electronics the 317's won't let you down.