78vette wrote:ap72 wrote:78vette wrote:You may want to look at Enginequest Vortec heads also. I just bought a set and ported them myself, (first time porting- followed info here and by Joe Mondello)
they flow 259 @ .400, 277 @.500. 286 @.600 on the intake with 1.94 valves. They are very nice castings and they have several combinations of intake faces and center bolt or perimeter bolt valve cover. I did not flow them before porting but they are supposed to flow as much or more than a stock vortec.
286cfm with a 1.94" valve?! That's incredible! Can you share some details? What depression were they tested at? Volume, min csa? Valve/seat angles/widths? Throat diameter?
I thought that was really high also. I am not an expert on this stuff by any means. If the exhaust wasn't so low I would not have believed the intake. They were tested at 28" with a 4.060 bore fixture. I opened up the push rod pinch to about 1.96, I did not check the port volume- I did not take a lot out of the ports, just cleaned them up with a carbide and then cartridge rolls and made everything nice and straight. The throat was 90% on the intake- because of the way the seat and bowl was in the exhaust I only opened them up to about 87%. I should have went with 1.6 on the exhaust and opened them up more because they did not flow as well.
I don't know the valve angles, a local guy with a good reputation (Kim Barr) did the valve job and the flow- I know it is a 5 angle. If you are really interested I could find out.
Here are the complete numbers.
.200 160/ 117
.300 217/ 143
.400 259/ 165
.500 277/ 171
.600 286/ 174
87 CFM at .100 is a pretty happy number so I would say his bench reads high.