Chevy Small Block Testing - Intake Manifold

Chevy Small Block Testing Trick Carb Nuts

Mr. Gasket also supplied some trick carb nuts that could be tightened easily by hand and then quickly snugged with an Allen wrench from the top.

Mr. Gasket also supplied some trick carb nuts that could be tightened easily by hand and t

Test 11: Wilson 1 1/4-Inch Open Spacer
Westech told us they've often seen improvements by adding a 1 1/4-inch open carb spacer (PN 000020) to the Air Gap manifold, so we thought we'd give it a try. Our results were not great, and power actually fell off just about everywhere. That probably means that the Air Gap's plenum was large enough for DM, and it didn't need the extra volume a 1-inch spacer added.

Test 12: Comp Cams Xe262h Cam
To either prove or disprove our theory on whether or not the engine needed more air to make more power we swapped in the next size larger COMP Cams XE262H Xtreme Energy camshaft (PN 12-238-2). The cam was 6 degrees bigger at 0.050 with 0.015-inch more lift and added a little more top-end power while giving away some low-end grunt. It was kind of a wash, but we think the motor liked the XE256H cam better, and it would definitely have driven better on the street with the extra low-end power of the 256 cam. However, since we plan to test new heads next month, we'll leave the 262 cam in place because it'll probably respond well to the better-breathing heads.

Westech has seen some extra power with these 1 1/4-inch-tall open spacers from Wilson Manifolds. It added a tiny bit of top-end power while giving up about an equal amount of bottom-end power.

Westech has seen some extra power with these 1 1/4-inch-tall open spacers from Wilson Mani

3rd Series Of Dyno Tests
We number each series of tests consecutively, starting with the number after the last of the previous month's tests. We'll also list the last test from the previous month, so you'll have something to compare the new tests to. So this month our first new test is number 9. Unless listed, no other changes were made for any test.

Test 8: Last test from last month. Weiand 8004 intake, COMP Cams 1.5:1 full-roller aluminum rockers, Carb Shop Q-jet, COMP Cams XE256H cam (256/268 adv duration, 212/218 duration @ .050, .447/.454 valve lift, 110 lobe separation, installed 2 degrees advanced), 1 3/4-inch Hooker Super Comp headers and Flowmaster 3 1/2-inch mufflers, 37 degrees total advance.

Test 9: Install Speed Demon 750 carb with 82/88 jets.

Test 10: Install Edelbrock Performer RPM "Air Gap" intake manifold.

Test 11: Install Wilson 1 1/4-inch-tall open aluminum carb spacer.

Test 12: Install COMP Cams XE262H cam (262/270 adv duration, 218/224 duration @ .050, .462/.469 valve lift, 110 lobe separation) straight up.

We played with the jets in the Demon carb trying to get the fuel curve to closely match the previous Q-jet carb. It ended up liking 82/88 jets.
We played with the jets in the Demon carb trying to get the fuel curve to closely match th
The Edelbrock Performer RPM Air Gap manifold went on next and produced great results (see:Test 10).
The Edelbrock Performer RPM Air Gap manifold went on next and produced great results (see:
We had to use some extra-thick valve cover gaskets and even then had to trim them to clear the intake manifold runners. It's no big deal, but just be prepared with some new thick gaskets and a razor blade when you make the swap.
We had to use some extra-thick valve cover gaskets and even then had to trim them to clear

Mr. Gasket has just released these new Ultra-Seal II intake gaskets (PN 810G). They're made from a stiff composite material, are reusable, and require no sealant at all to work. We had the intake on and off several times, and they sealed perfectly each time.
Mr. Gasket has just released these new Ultra-Seal II intake gaskets (PN 810G). They're mad