Danger Mouse Part 7 - Maximum Trade-Off

Messing With Rocker Ratios And Bigger Cams

Mike Petralia Mar 1, 2003 0 Comment(s)

Last Month's Power Recap
DM's fifth bash on the dyno last month ended with a maximum 416 hp and 440 lb-ft of torque. Those are fantastic numbers coming from a 9.25:1 small-block running a very small hydraulic camshaft (the XE262H). The Vortec heads have made 30 more peak horsepower than the other set of "factory" heads we tested-the camel humps (see Test 12, December '02). Also, last month's average power ended up at 333 hp and 417 lb-ft (see Test 15).

This month we tried a new Wilson carb spacer and gained some extra power at 3,000 rpm (Test 16). We wrestled rocker arm ratios around like they were going out of style and saw some torque improvement with no horsepower losses (Test 17). And we finally swapped in a bigger cam with the results we were expecting (Test 18), more horsepower upstairs and less torque downstairs. As usual, if you feel you've got an idea for us to try, send it in and we'll tackle it in the upcoming months.

Sucp_0303_09_z Small_block_chevy Dyno_chart 4/12

6th Series Of Dyno Tests
We'll number every series of tests consecutively, starting with the last number of the previous month's tests. We'll also list the last test from the previous month so you'll have something to which to compare the new tests. So this month, our first new test is number 16. Unless listed, no other changes were made for any test.

Test 15: Last test from last month. Vortec iron heads: Scoggin-Dickey PN SD8060A (64cc chambers, 170cc intake runners, 1.94/1.50 valves), Edelbrock RPM Air-Gap Vortec manifold, Speed Demon 750 carb, 1 1/4-inch open Wilson spacer, COMP XE262H cam (262/270 adv, 218/224 at .050, .462/.469 lift, 110 lobe separation) straight up. COMP 1.6:1 Magnum roller-tip rockers.

Sucp_0303_10_z Small_block_chevy Dyno_chart 5/12

Test 16: Install Wilson four-into-one tapered carb spacer.

Test 17: 1.5:1-ratio exhaust rockers, 1.6:1-ratio intake rockers (best results of all rocker ratios tested).

Test 18: Install COMP Cams XE268H camshaft (268/280 adv, 224/230 at .050, .477/.480 lift, 110 LS) straight up. Changed all rocker arms back to 1.6:1 ratio.

Send your test suggestions to:
Super Chevy Magazine
Attn: Danger Mouse
720 Hundley Way
Placentia, CA 92870

Or Email:
mike.petralia@primedia.com

Sources

Westech Performance Group
Mira Loma, CA
951-685-4767
WestechPerformance.com
Comp Cams
Memphis, TN 38118
800-999-0853
http://www.compcams.com
Wilson Manifolds
Ft. Lauderdale, FL
954-771-6216
http://www.wilsonmanifolds.com
Mechanix Wear
Valencia, CA 91355
800-222-4296
www.mechanix.com
76 RACING FUELS & LUBRICANTS

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