Keep in mind that different people flow test with different methods.

Rally1200's flows where acheived with 32" water

The head on my race car was done from a GX, it flows 166 cfm @ 28" water @ .480" lift on the inlet with 39mm valve, not sure on the port size though, will take some measurments next time the manifold is off.

OK!! This is looking like its going to go somewhere! This might make a good article for the tech section.
Yep, I've got the idea about the different test pressures. The fine print at the bottom of Rally1200's flow chart actually mentions this aswell and gives a factor of 0.935 to convert flows at 32" H20 pressure back to 28" H20.

I've done fluid dynamics at uni and I'm pretty sure that the conversion factor is the square root of "new pressure"/"old pressure". ie as above sqrt(28/32)=0.935414. So we can compare flow data tested with different test pressures.

So MLS, your head would flow about sqrt(32/28)*166 = 177cfm at 32" H20 pressure with 0.480" lift.

ya, i agree. no much porting and polishing data on tech section.

Ok port sizes are

Exhaust 27.5mm X 32mm

Inlet 31mm X 39mm

I should be able to get a pic of it on the weekend.

MLS ??

OK,

remeasured and found head spec sheet

In valve - 40mm
Ex valve - 32mm

Port sizes at manifold (W x H)
Inlet - 32 x 40
Exhaust - 29 x 31

Flows @28" water
Inlet - 166 @ .480"
Exhaust - 106 @ .460"


not using this engine anymore, not worried about giving away 'racing secrets', so here's a pic for you

Oh, and this is what the engine looked like before a season's of racing....

wwoooo, sure is a nicely presented engine MLS! Would you by chance have all the flow values at different lifts, like Rally1200's at the top of this post??

C'mon people. I'm still needing some more info to make a good correlation of port size v flow. Big thanks to those people who have added stuff already.

From the books I've been reading, for valve lifts below 0.25 x valve diameter the flow depends mainly on the valve size and shape around the valve seat. For lifts above this value, the flow depends mostly on the port size and taper within the head.

one last bump.