View Full Version : Diffuser

04-02-2011, 12:07 PM
Have been doing some bench testing on a set of heads I'm playing with.

Shop is Chevy dominated with no Ford fixtures.

Was able to rig the small block intake with dum dum for the intake side.

Exhaust has been flowed without.

Anybody ever flow test with and without so I could get a feel for variance in the test numbers up or down.

Could any responses state stock or bigger valve that was tested as that may change the numbers.

Tks in advance

04-03-2011, 07:29 PM
Just some background, Exhaust will not be checked with a fixture. (don't have)

Intake side uses a fixture.

Heads have been tested as Stock- Cleaned - Hit/Vertical unshrounding (seat cut).

I have had good luck with intake.


All at 500
225 at 600- 229 at 650

Exhaust is Horrible- H/V 144 155 at 600- 166 at 650

Next flow (this week) ) I have put a 45 on the unshrouding,

I'm expecting a significant jump with the last cut for the exhaust. It appears to be buried thru 350-400 lift behind the wall.

Apples to Apples I don't have, due to the fixture being present on the intake side and not on exhaust.

As mentioned earlier what does the fixture change.