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Small Block Chevy Parts Testing - Total Recall: Danger Mouse Part 9

A Recap Of Danger Mouse Tests

Mike Petralia May 1, 2003



















Sucp_0305_02_z Chevy_small_block_part_9 Dyno 2/7

There was a time, not that long ago, when engine dynos were considered a black art. Not everyone believed in what the dyno had to offer, and some thought of dynos as nothing more than hocus-pocus. Aren't you glad we don't live in those dark ages anymore? Today, dynos are everywhere and the reality of dyno racing-i.e. trying to make more and more power on the dyno, just like trying to go faster and faster on the track-has become an art form of its own. At SUPER CHEVY we may not have our own dyno, but we still wanted to be able to test any and every part we could think of, just to see what would happen.

And we wanted to get you involved in the most important aspects of our tests. So we built an engine and crowned it Danger Mouse (DM), in reference to the fact that it will be risking its life just to test any hair-brained idea we might come up with. Then, we asked you to send in your ideas on what we should test next. So far it's been fantastic. Your initial response was a bit skeptical, and some sent letters calling us fools, claiming that there's no way we'd ever test their ideas. These same folks submitted ideas for engine combinations that we knew from previous testing wouldn't work. So in fact, a few of the nay-sayers were correct. We won't test every idea, just the ones that make sense. But we've also gotten tons of great ideas from your letters and can't wait to see more. So keep sending them in.

With more than six months of testing behind us, we thought now would be a good time to recap the highlights of each test to show you some of the best combinations to build. Basically, what we're offering in this month's installment are recipes for how to get your street small-block to produce anywhere from 300 to 425-plus hp and more than 440 lb-ft of torque, all on a budget and all with easy-to-find, off-the-shelf parts.

Sucp_0305_04_z Chevy_small_block_part_9 Motown_block 3/7

Danger Mouse had to be strong to survive. We spared no expense and equipped DM to handle the toughest assignments with a World Products four-bolt Motown block.

Racap From The Beginning
From the outset we knew DM would see a lot of abuse, and we've logged over 275 full-throttle pulls, along with countless, unmeasured others, without a single failure. Such reliability can only be attributed to one cause, the best parts. When building DM, we stressed the importance of selecting the highest-quality components to ensure a long dyno life. The World Products Motown four-bolt block, complete Lunati forged rotating assembly, and Milodon high-volume oil system have performed flawlessly and helped DM produce consistent results month after month, and we thank them for it.

Since no dyno comparison of this type would be worth diddly if we didn't have some stock power figures to base our results on, we first equipped DM with the barest of bone-stock top-end parts. A set of reconditioned factory-iron "camel hump" heads (casting No. 461) from Powerhouse Engine Components breathed through a bone-stock iron GM intake fueled by a professionally prepped Q-jet from the Carb Shop. The reason we chose this carb was to avoid the hassles of spending hours tuning the carb on the dyno, and the Carb Shop Q-jet worked flawlessly, fueling DM into the 350-plus-hp range. After we felt we had a reliable stock baseline to compare figures to, we dove head-first into testing cams, cylinder heads, carbs, rocker arms, spacers, and manifolds, because that's what we felt most of you would like to see.

We've learned a lot from these tests and are sure we'll learn plenty more. Soon we plan to start applying the pressure to DM when we go with blowers and nitrous oxide setups to prove their worth. We'll also start messing around with bottom-end components, changing pistons and rod lengths to see what effect they can have on a stock-stroke small-block. So, as we've asked you every month for more than half a year now, send us your ideas, thoughts, comments, and criticisms for DM. Otherwise, we'll be left to our own devices to figure out what to do next.

Dyno Tests
Danger Mouse Stock Baseline (Test 1) Profile:
Compression: 9.4:1
Heads: stock 461 "camel hump" castings
Cam: COMP Cams 246PE cam (246/263 adv duration, 203/212 duration @ .050, .429/.438 valve lift, 110 Lobe separation)
Intake: Stock iron
Carb: Carb Shop Q-jet
Ignition: Proform HEI, Champion No.14 plugs
Fuel: 76 Performance, 92 octane
Ignition Advance: 37 degrees
Exhaust: 1 5/8-inch Hooker headers into 3-inch Flowmaster mufflers

Sucp_0305_05_z Chevy_small_block_part_9 Lunati_piston 4/7

The rotating assembly also had to be up to the task, so we chose a complete Lunati forged kit with a 3.48-inch stroke crank and 5.7-inch rods. The Lunati pistons have four-valve reliefs and have yielded between 8.9 and 9.4:1, depending on the cylinder heads used.

Tests 1-4: Baseline, new intake manifold, roller-tip rockers, retard cam 2-degrees (October 2002).

Test 1: This represents what a typical 355-cid small-block would make if it had just been blueprinted but still had most of its stock components.
Max 395 tq, 308 hp
Avg 376 tq, 266 hp

From this point on, except for the changes listed, nothing else was touched.

Test 2: We installed a Weiand PN 8004 dual-plane intake manifold and leaned out the Q-jet.
Max 394 tq, 325 hp
Avg 380 tq, 270 hp

Test 3: We replaced the stock stamped-steel rocker arms with COMP Cams 1.5:1 roller- tip Magnum rockers.Avg 390 tq, 278 hp

Test 4: We retarded the cam 2 degrees.
Max 405 tq, 349 hp
Avg 390 tq, 278 hp

Sucp_0305_06_z Chevy_small_block_part_9 Cam 5/7

Danger Mouse has seen four different cams so far, and it loved every one of them. Even though it keeps making more power and revving higher the bigger we go, we're still well within the realm of street-worthy cams with these tests.

Tests 5-8: Bigger 1 3/4-inch headers, full-roller rockers, bigger XE256H cam, stud girdle added (November 2002).

Test 5: Installed larger 1-3/4 Hooker headers. Compare Tests 4 and 5 and you'll see that average torque was down by 2 lb-ft, but peak toque and horsepower were up slightly, and average horsepower increased by 9. That's a fair trade to us.
Max 407 tq, 351 hp
Avg 388 tq, 287 hp

Test 6: Swapped in COMP Cams full-roller 1.5:1 aluminum rocker arms. Peak and average power didn't change at all (compare Tests 5 & 6), but we did get 5 more lb-ft of torque at 3,200 rpm.
Max 407 tq, 351 hp
Avg 389 tq, 288 hp

Sucp_0305_07_z Chevy_small_block_part_9 Intake_manifold 6/7

Edelbrock told us they've worked very hard to ensure equal runner sizes in all its Performer RPM Air Gap manifolds. We certainly believe them, because bolting this manifold on netted us the single largest horsepower and torque gains from any test yet.

Test 7: A COMP Cams XE256H cam (256/268 adv duration, 212/218 duration @ .050, .447/.454 valve lift, 110 lobe separation) was swapped in, 2 degrees advanced, and we were rewarded with lots of grunt (compare Tests 6 & 7).
Max 413 tq, 357 hp
Avg 396 tq, 293 hp

Test 8: This was our very first weird test. We witnessed that the 3/8-inch screw-in studs in the heads were flexing as we lashed the valves, so we hypothesized that it might kill some lift and duration. In an attempt to prove our hypothesis correct, we installed a COMP Cams stud girdle. Power and torque fell off at most rpm, so the stud girdle was later removed.
Max 413 tq, 356 hp
Avg 395 tq, 292 hp

Sucp_0305_09_z Chevy_small_block_part_9 Cylinder_heads 7/7

GM's Vortec iron cylinder heads are cheap and powerful. Pictured here are all the parts you'll have to buy to run the Vortecs, because they won't work with the regular parts you may have lying around.

Note how DM's powerband slowly increases as we keep trying different parts.

Tests 9-12: Bigger carb, "Air Gap" manifold, new carb spacer, bigger XE262H cam (December 2002).

Test 8 ended the day with a maximum 356 hp and 413 lb-ft of torque, and average figures were 292 hp and 395 lb-ft. This month we tried a new Speed Demon carb and an Edelbrock Performer RPM "Air Gap" manifold with a Wilson 1 1/4-inch open spacer. We also installed the next-size-larger COMP Cams Xtreme Energy camshaft. The final reward was a new max 386 hp and 438 lb-ft of torque, and the new averages were 316 hp/416 tq. Now we've got this stock iron-headed 355-cid Mouse making almost 390 hp and 440 lb-ft of torque! So far this looks like the best power formula with the stock heads, particularly since the motor didn't respond that well to the bigger cam. That means that we just about maxed out the stock cylinder head's flow potential and would either have to go in and start porting or install a new set of performance cylinder heads for more power.

Test 9: Installed Speed Demon 750 carb with 82/88 jets.
Max 418 tq, 356 hp
Avg 398 tq, 294 hp

Test 10: We installed an Edelbrock Performer RPM "Air Gap" intake manifold, which was the best single-gain swap yet and the first test to average over 400 lb-ft of torque.
Max 438 tq, 380 hp
Avg 416 tq, 315 hp

Test 11: We installed a Wilson 1 1/4-inch-tall open carb spacer.
Max 437 tq, 381 hp
Avg 414 tq, 314 hp

Test 12: A larger COMP Cams XE262H cam (262/270 adv duration, 218/224 duration @ .050, .462/.469 valve lift, 110 lobe separation) was installed straight up.
Max 438 tq, 386 hp
Avg 416 tq, 316 hp

Unlucky Test 13: S/R Torquer cylinder heads (January 2003).By Test 12 we had really started to crank out some power, especially considering that DM still wore its stock iron heads and ran a mild camshaft. However, Test 13 really did prove to be an unlucky number, and we were taught a lesson in proper parts matching. The S/R Torquer cylinder heads (which we got from Bill Mitchell's Hardcore Racing Products for only $415 each) set us back a few ponies, probably the result of combustion chambers and valves that were too large compared to the stock heads.

Test 13: World Products S/R Torquer cylinder heads (PN 042660-2 67S) were installed (67cc chambers, 170cc intake runner volume, 2.02/1.60 valves). No other changes were made.
Max 417 tq, 379 hp
Avg 399 tq, 303 hp

Test 14-15: GMPP Vortec cylinder heads and COMP Cams 1.6:1 rockers (February 2003).

Since power fell off drastically in January's test, we knew we'd made some mistakes and had to redeem ourselves. To accomplish this we went back to The General and installed a new set of iron GMPP Vortec cylinder heads. We compared figures to the stock "camel hump" heads (Test 12) and found that even though the Vortecs actually dropped DM's compression by about 1/4-point to 9.25:1, that didn't stop them from adding more power. Then we swapped on our first set of 1.6:1-ratio rockers (previously only 1.5:1-ratio rockers would fit, due to pushrod interference) and were, once again, rewarded with more power.

Test 14: We installed iron GMPP Vortec heads (SDPC PN SD8060A, 64cc chambers, 170cc intake runner volume, 1.94/1.50 valves) with COMP Cams 1.5:1 Magnum roller-tip rockers (PN 1417-16) and an Edelbrock RPM "Air Gap" manifold (PN 7516).
Max 435 tq, 409 hp
Avg 413 tq, 330 hp

Test 15: COMP Cams 1.6:1 Magnum roller-tip rockers (PN 1418-16) were installed.
Max 440 tq, 416 hp
Avg 417 tq, 333 hp

Test 16-18: GMPP Vortec cylinder heads, Wilson four-into-one carb spacer, COMP Cams 1.6:1 rockers (March 2003).

The final dyno bash we'll review this month had us swapping cams, rockers, and carb spacers like they were going out of style. DM ended up making a maximum 427 hp and 439 lb-ft of torque. Those are fantastic numbers coming from just a 9.25:1 small-block still running a very small hydraulic camshaft (COMP's XE268H). The Vortec heads had made 23 more peak horsepower than the factory heads we tested-the camel humps (compare Tests 12 and 14).

In March '03 we tried a new Wilson carb spacer and gained some extra power at 3,000 rpm (Test 16). Then, we wrestled rocker arm ratios around and saw some torque improvement with no horsepower losses (Test 17). And we finally swapped in the next bigger COMP cam with the results we were expecting (Test 18), more horsepower upstairs and less torque downstairs.

By Test 18 we think we've reached the pinnacle of affordable small-block performance, and to make any more power we'd have to go with ported cylinder heads and/or a set of more-expensive aftermarket aluminum or maybe still some iron castings. Look for these comparisons in upcoming months. Still, if you follow our recipe, any properly blueprinted, pump gas small-block you build could easily duplicate all of our power figures, while costing only around $3,500 and being a kick to drive everyday.

Test 16: A Wilson 1-inch open carb spacer with a Wilson four-into-one tapered spacer were swapped in.
Max 440 tq, 414 hp
Avg 418 tq, 334 hp

Test 17: We tested 1.5:1-ratio exhaust rockers and 1.6:1-ratio intake rockers (best power of all rocker combinations tested so far).
Max 442 tq, 414 hp
Avg 419 tq, 335 hp

Test 18: A COMP Cams XE268H camshaft (268/280 adv, 224/230 @ .050, .477/.480 lift, 110 LS) was installed straight up. We changed all rocker arms back to a 1.6:1 ratio.
Max 439 tq, 427 hp
Avg 418 tq, 335 hp

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


Westech Performance Group
Mira Loma, CA
Comp Cams
Memphis, TN 38118
The Carb Shop
Ontario, CA
Wilson Manifolds
Ft. Lauderdale, FL
Powerhouse Products
Memphis, TN 38118
Springville, NY 14141
Mechanix Wear
Valencia, CA 91355
Lunati LLC
Olive Branch, MS
Simi Valley, CA 93065
Specialty Component Engineering
Lancaster, CA 93534
Specialty Auto Parts
Roseville, MI 48066



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