04-06 3500 flow numbers

[SappySE107]

This might interest some of you.

Stock Head flow numbers



Stock vs ported manifold comparison

[USMCGrunt0307]

Kinda confused but is this sayin that the intake alone doesnt really need to be ported and that the major bottleneck in the intake side is the heads?

For instance, its saying the intake flows at 216 CCFM at .50 lift but with the intake on the heads, it only flows at 176.7 (and even 192 when ported).

So basically what this means is that in order to take full advantage of the intake, somebody needs to redesign the heads or when porting, enlarge them even more...if possible?

[SappySE107]

no, it doesn't mean that at all. The 3500 heads flow a lot. You will have a restriction on the intake manifolds because of the surface area (friction) and size/shape. You would need 6 throttle bodies and velocity stacks to get the full amount of air as testing the head alone. You will notice that the low lift flow increases with the manifold, especially ported. This is because I took the time to find the best port shape.

.500 lift flow numbers are all but worthless, especially on a stock cam that won't even see .450 lift. You want to have the best low/mid lift flow and the smallest ports/runners to support the air flow. Velocity means a hell of a lot, especially on the NA motors. You don't want to hog everything out for more CFM if it cuts your speed down. The speed is what helps get the extra push of air/fuel into the cylinder as the piston is coming back up the cylinder and the intake valve is closing. This is why the mid/low lift numbers matter. You can go a step further and use the better low lift flow to delay the valve timing events and make the most of your compression stroke.

If you compare your stock heads alone agains the 3400 heads (gen 3 vs your gen 4), you would understand why the 3500 heads are so bad ass. Have you guys seen any pictures of your engine parts? We have a gallery of pics on 60V6.com as well. LS1 like combustion chamber, and exhaust port/runner.

[Blackrider]

Tanks for the info man!
I'm going to move this to tech specs. Thanks again!

[SappySE107]

no problem 114.4 cc for the stock 3500 intake port and 68.6 cc for the stock 3500 exhaust port. Stock 3500 combustion chambers are 32.4 cc. Stock plenum port is 2.09 sq in. Ported is 2.68 sq in. I have run simulations in dynomation and it is what I use to help me figure out port dimensions vs flow. Good stuff

[Bowtie Boy]

good stuff! Do you have any flow/port/comb. chamber specs/flow numbers for the 3.9L?

I assume those bench numbers are at 28" of water?

[SappySE107]

Yes, 28" of water with a clay molded entrance for the head specs alone. The intake numbers are with both manifolds, and all the other ports/openings are blocked off.

My current flow bench is 94mm bore, which is good for the 3500, and still pretty good for shrouding when testing the 92mm 3400. I need to make a new box setup for the 99mm bore. I pretty much only do 60V6 engines so I haven't needed to adjust my setup till now.

Have you seen pictures of the 3900 heads?