vortec head and its limits....

[D&A Machine Shop]

Still can't get my scanner to work :x so I'm gonna do this the hard way.
This is the power figures on one of our 350 vortec headed dirt track engines, the heads are unported. The rules on these engines require stock heads so we have spent a lot of time with R&D work to find the right combination on these engines.

4000.422tq.322hp
4200.434tq.352hp
4400.444tq.374hp
4600.452tq.384hp
4800.457tq.419hp
5000.456tq.435hp
5200.460tq.457hp
5400.458tq.471hp
5600.454tq.484hp
5800.447tq.495hp
6000.436tq.499hp
6200.421tq.497hp
6400.407tq.496hp
6600.393tq.495hp
6800.374tq.485hp

 

[cutlass389]

I bet that's got a pretty hairy cam to get that high with stockish vortecs. Peak torque at 5200? :shock:

 

[D&A Machine Shop]

:lol: Yep you are right about the cam, These engines don't make very much torque
below 3500 so it's not much use in a street car but the dirt track guys love it.
But they usually come out of the corners at 4000 and hit around 7000 to 7400
by the end of the straight.





This was my 100th post. :nana_wrench:

 

[cutlass389]

I was sorta' right. Even with a freakishly large cam the vortecs were done making MORE hp around 56-5800 rpms. They continue to make about the same power level up 'til 7000 due to the fact that the intake valve is open for so long(time) but cannot move enough air(volume) to produce additional levels of power. I believe that the optimal cam for vortec heads would be around 230* @ .050 intake, 240* @ .050 exhaust, lift for both about .500ish, with the LSA between 104-106* and the intake on a 102* LCA. They need about 10* more help on the exhaust side(stock), and the generous overlap will help the 1.94" intake valve(stock) fill the cylinder. This cam should reach up to 6000 but yet still be effective as low as 2000. This is hydraulic roller territory with reasonable spring pressures to boot. Probably even have best overall and average results with an RPM dual-plane manifold. $.02.