On our first pull, the 150hp tune netted exactly that with a 482hp peak. This left us only 18 shy of our 500hp goal, and after a discussion with Westech's Steve BrulÚ we felt brave enough to hit it with a full 200 shot. This required a simple swap to 0.082 fuel and nitrous jets with the timing yanked back to 24 degrees. All that paid off with a very successful 520hp number. You'll note that we didn't hit the nitrous until over 5,000 rpm, as we were only interested in a peak horsepower number. The advantage with nitrous flowing through a fixed orifice is that the same amount of nitrous at a lower rpm generates a tremendous increase in torque. That doesn't show up in this test, but if you look at the torque increase at 5,200 rpm, you'll see there's an additional 200 lb-ft that generate the additional horsepower. That same torque gain at 3,500 rpm would kick it up to almost 550 lb-ft. We felt those cast ring lands might fail with this much torque at a lower engine speed, so we elected to delay the nitrous until 5,000 rpm. Pulsed controllers or staged nitrous systems offer the same kind of protection. A boneyard HEI provided the ignition after we did some work to free up the advance mechanism. We added a new cap, a rotor, and Summit spark-plug wires but retained the original coil.A boneyard HEI provided the ignition after we did some work to free up the advance mechani Before bolting our Scoggin-Dickey Goodwrench engine on the dyno, we treated it to an honest Chevy Orange paintjob. For testing peace of mind, we used Westech’s 17⁄8-inch primary tube dyno headers fitted with thermocouples, oxygen sensors, and Flowmaster mufflers. We also tested a set of Hedman 15⁄8-inch Chevelle headers that we will use in the car and saw a small increase in torque but no real change in peak horsepower.Before bolting our Scoggin-Dickey Goodwrench engine on the dyno, we treated it to an hones Brule also noted how badly the engine fell off after peak horsepower with the 200 shot. This indicates the engine is maxed out in terms of what we could expect if we tried to feed this engine even more nitrous. Effectively, we have arrived at the point at which the stock exhaust ports are not capable of pushing more spent gas out, especially at high engine speed when there is less time for that to occur. This leaves a greater percentage of the exhaust gas in the chamber during the intake session, thereby reducing power. Effectively, the nitrous horsepower limit for most street engines is roughly 75 to 100 percent of normally aspirated horsepower. We've got some further plans for our Saturday Night Slayer, including a set of forged pistons to give us some detonation durability and a better set of iron Vortec heads. This engine has far more potential with a set of better heads and the iron GM Vortec heads are both affordable and offer dramatically better flow potential. The smaller 64cc chamber will also jack the compression a little and with a good dual plane, we could be very close to 400 hp normally aspirated. By The Numbers Test 1: This is the Goodwrench engine baseline using a factory Q-jet manifold and Q-jet 750-cfm carburetor with 1-5/8-inch Hedman headers and a pair of 2-1/2-inch Flowmaster mufflers. Test 2: The change for this test was the Summit camshaft, a new Weiand single-plane intake, and a previously owned 750-cfm Holley mechanical-secondary carburetor. Total timing was 37 degrees with 72 primary and 76 secondary jetting in the carburetor. Test 3: Now we get serious, bolting on the NOS Cheater system with 200hp jetting and 24 degrees of total ignition timing. The retarded timing explains why the power is down below 5,100 rpm where the nitrous was introduced. RPM Test 1 Test 2 Test 3 TQ HP TQ HP TQ HP 2,500 265 126 318 151 310 147 2,700 269 138 317 163 311 160 2,900 310 171 317 175 313 173 3,100 299 176 330 195 316 186 3,300 294 185 334 210 320 201 3,500 307 204 341 227 324 216 3,700 348 245 348 245 331 233 3,900 336 249 353 262 333 248 4,100 325 254 355 277 334 261 4,300 310 254 354 290 335 274 4,500 296 253 350 300 332 285 4,700 276 247 345 309 330 296 4,900 259 241 341 318 338 315 5,100 239 232 335 325 379 368 5,300 218 221 326 329 520 525 5,500 -- -- 317 332 482 505 5,700 -- -- 305 331 450 488 5,900 -- -- -- -- 420 472 Peak 348 254 355 332 520 525 Avg. 290 213.1 337.6 281.5 N/A N/A Bottle pressure is a major tuning factor with nitrous. We used Westech’s bottle heater using hot water to maintain the bottle temperature at 92 degrees to maintain pressure at 950 psi. We used our Craftsman temp gun to measure bottle temperature.Bottle pressure is a major tuning factor with nitrous. We used Westech’s bottle heater usi Brule showed us this trick for checking solenoids. With the engine off and the bottle closed, hit the button and hold a thin feeler gauge above each solenoid. The magnetic field will attract the feeler gauge to the solenoid.Brule showed us this trick for checking solenoids. With the engine off and the bottle clos Broken pistons have taught us that non-projected nose, cold-range spark plugs will light the fire just fine and will not cause pre-ignition and detonation problems. This Autolite AR132 plug is a 200hp shot survivor and looks very happy.Broken pistons have taught us that non-projected nose, cold-range spark plugs will light t Parts list Description PN Source Price Goodwrench long-block, pre-'86 10067353 Scoggin-Dickey $1,499.99 NOS Cheater nitrous system 02001NOS Summit Racing 539.95 10-pound bottle fill N/A Orme Brothers 50.00 Summit budget cam SUM-1105 Summit Racing 54.95 Weiand X-celerator manifold 7547 Summit Racing 159.95 Holley 750 mech. sec. carburetor 0-4779 Swap Meet 150.00 Hedman 1-5/8-inch header, painted 68299 Summit Racing 169.95 Summit header gasket, copper 111406 Summit Racing 22.95 Summit intake gasket G2410 Summit Racing 12.95 Summit carb gasket G1418 Summit Racing 1.95 Fel-Pro head gasket 1094 Summit Racing 34.99 GMPP water neck 10108470 Summit Racing 6.95 Mr. Gasket thermostat, 180 4364 Summit Racing 13.95 HEI distributor used Boneyard 15.00 MSD HEI cap, rotor 8416 Summit Racing 26.95 Summit spark plug wire set 868836 Summit Racing 29.95 Autolite spark plugs AR132 Summit Racing 28.00 Wix oil filter 495-51060 Summit Racing 4.95 Comp Break-In oil, 10W-30, 5 qts 1590 Summit Racing 29.75 Harmonic balancer 594-012 Summit Racing 31.95 Summit balancer bolt G1677 Summit Racing 5.95 Gates water pump 43101 Boneyard 24.79 Total Rock Auto $2,915.82 SOURCES Orme Brothers Inc. 18453 Parthenia Place Northridge CA 818-885-1414 OrmeBrothers.com Hedman Hedders 12438 Putnam Street Whittier CA 90602 562-921-0404 www.hedman.com Holley Performance Products/Brands 1801 Russellville Rd. Bowling Green KY 42101 270-781-9741 www.holley.com Comp Cams 3406 Democrat Road Memphis TN 38118 800-999-0853 www.compcams.com MSD Ignition (Autotronic Controls) 1490 Henry Brennan Drive El Paso TX 79936 915-857-5200 www.msdignition.com Scoggin Dickey Parts Center 5901 Spur 327 Lubbock 79424 800-456-0211 Summit Racing PO Box 909 Akron OH 44398 800-320-3030 www.summitracing.com « | 1 | 2 | View Full Article By Jeff Smith Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!
mrduck05 8/23/2012 at 8:42 PM Very informative but I do have one bit of criticism. Whenever you guys build an engine with stock heads you never list the casting numbers. That info would help alot.
