Just a theory question, not enough money to actually do it but i was wondering if putting these heads on the truck would be worth it? Picking up 18cfm at .400, 31cfm at .500, and 45cfm at .600 all with a smaller cc intake runner than stock. Wouldn't the increased velocity help throttle response and low end torque?? Also these flow numbers were on a smaller bore. than the 6.0. same question for the edelbrock 215cc?

 

Those would be awesome heads for the exact reasons you've listed. 205cc runner versus 210cc on the stock 317s I believe. You could probably pick up a used set for $1800

 

How much more would these heads flow on the bigger bore? the stage II CNC from West Coast flow a hair better but the runner ends up at 233cc's i think or 237 cant remember. What are the stock valve sizes on the 317 heads?

 

2"/1.55" on the valves

I dont know on the flow, but I've heard of people swapping them from their 346 onto their 408 with great results.

 

Smaller runners wil help with low end torque. Higjher flow will help top end. Heads are the best way to make more power on N/A motors.

 

wonder how that type of motor would like a whipple or magnacharger afterwards, would it kill the power cause of compression or would it increase the velocity???

 

I have a friend with a Silverado SS 2wd. Stock bottom end ,afr 205's, comp XER 224/228 112 lsa .588 lift, dynatech headers with high fllow cats, magnaflow exhaust, vigilante 3000 10.5 inch converter, underdrive pulley, K&n CAI, 42lbs injectors. Stock manifold and t/b. Put down over 400lbs torque to the wheels @3000 rpm and peaked around 430 through stock 20 in wheels. The horsepower peak wasn't real impressive at 380 rwhp ,but, it is a beast on the street. He laid waste to another SS with L92 heads , manifold combo with custom spec big cam and off road exhaust. And when I say laid waste , I mean he put bus lengths on him from a dig and run out of site on the top end. Simple conservative combo that works. Don't go too big on the head runner size and keep the camshaft mild and you will be much happier with your truck. Low end torque is where it's at with heavy vehicles.

 

VERY INTERESTING AND I AGREE WITH YOU IN THAT SIMPLE CONSERVATIVE COMBOS ARE BEST FOR THE STREET AND ALOT MORE FUN TO DRIVE...

 

That is the exact reason I have been looking at these heads as well the 205cc runners are what I need to bump up my low end a tad to get my 2500HD moving faster and the bump in compression will help too!

Also do does anyone know if they clear aftermarket rockers I had to grid some material down on my stock 317's and get valve cover spacers for my 1.7 hs rockers.

 

I had to modify the oil baffles to clear my Comp stainless rockers. The stock valve covers need work, but the AFRs have plenty of clearance.