[Keithc8]

Heads are flow at inches of water which is different than the vacume on an engine. The heads we do are flow tested on an 4.250 bore fixture. People flow heads at 10, 25 and 28 inches with 28 being the most common. You also have to use a radius entry on the intake because the sharp edges of the port opening will cause problems and it is not run like this on the engine. The exhaust is also flowed with a exhuast ipe stud and without. The exhaust will flow more with the exhaust pipe stub which is normally about 6 inches and similiar in size to the exhaust to be used. There are several types of flow benches and the flow will vary a little on all. The main thing is to use the same bench to test results and then how they affect the engine.
We will normally use a 2.19 or 2.25 intake valve and a 1.75 exhaust and this is no problem on the 4.250 bore. The Edelbrock stage three heads are normally done with a 2.250 and 1.750 valve. I can give you the flow real close of the top of my head and this will vary a little depending on the lift to be run because this affects the valve job we use. Intake flow 210/.300, 275/.400, 320/.500, 345/.600, 360/.700, 375/.800 and exhaust with a 2x6 exhaust pipe stub, 160/.300, 220/.400, 245/.500, 260/.600, 270/.700, 282/.800. Like I said we can vary this some with the valve job depending on the use of the heads. We also run some 11/32 valves when we are trying to max the top end flow and get the weight down on the valve as well as titanium valves. We use our stage two Edelbrock heads quite a bit on the street engines because they will flow a little better than the stage three heads at .200/.300/.400 lifts but not as good at the .600/.700/.800 lift range. The Blue Thunder heads we have done we set up for a .600 lift type of street strip engine and they flowed real good to .600 lift, they were a little better than the stage two Edelbrock on the intake and almost as good as the stage three Edelbrock on the exhaust. Hope this helps a little. Thanks, Keith