In our last episode, Godzilla, HOT ROD's 540ci big-block Chevy pump-gas engine, reached a high of 695 hp equipped with Brodix BB-2 Plus rectangular-port heads, an Edelbrock Victor Jr. intake with a 1-inch open spacer, a Holley HP Ultra 950-cfm carburetor, a Lunati solid roller cam (255/263 degrees at 0.050), and Hooker headers with 21/8-inch primary tubes into 31/2-inch collectors. Using a Performer RPM Air-Gap and 2-inch primary-tube Hookers, the engine made 691 lb-ft but was down 17 hp. To fully utilize the top-end potential of the big rectangular ports would require an induction system upgrade. And with improved induction, the engine could support an even larger cam. With a bigger cam, we wanted to try even larger heads. And with larger heads, we could jump up yet again on the cam. Climb onto the high-performance merry-go-round and watch as we claw our way up the performance treadmill to just under 800 hp with the help of Speed-O-Motive.
In its ultimate 793hp trim, the pump-gas 540ci Rat made its best numbers with a Scat crank and rods, JE/SRP pistons, a huge Comp solid roller cam, a Dart intake, a 2-inch open spacer, a Performance Carburetors 1,050-cfm Holley Dominator, Hooker headers with 21/8-inch primary tubes into 31/2-inch collectors, a Milodon oil pan, and a Professional Products damper.
Time For A DominatorTorque and power output was not as good with any one intake as it was with the oval-port Race-Rite heads when equipped with a Wilson Manifolds-modified oval-port version of the Victor Jr. Wilson had reworked the intake to match the superior flow characteristics of the rectangular-port version of the Victor Jr. Originally, we attributed part of the performance discrepancy to a 0.81-point difference in static compression ratio: The Race-Rites had previously been milled to 109 cc for another project, but it was thought the rectangular-port BB-2 Plus heads were virgin, uncut castings. During the course of the latest test session at Speed-O-Motive, we discovered these heads had also been milled sometime in the past to 112 cc, yielding only a measly 1/4-point static compression difference (10.93:1 for the Race-Rites versus 10.67:1 for the BB-2 Plus heads). Such a small difference further confirmed our belief that the induction system was the main performance bottleneck.
Moving to serious race intakes, Speed-O-Motive first tried a Dominator-flanged Victor 454-R (PN 2907, left). Edelbrock designed this intake for drag racing and serious marine use, with a claimed operating range of 3,500-8,000 rpm on a typical 454. On Speed-O-Motive's DTS dyno, the 540 easily pulled it from 2,500 and made power through 6,300.
So we pulled out the big guns, bolting on a couple of Edelbrock 4500 Dominator-flanged intakes, a Victor 454-R, and a Super Victor. From here on out, the engine consistently preferred 21/8-inch primary-tube headers over 2-inch headers. Making the transition in stages, first an adapter was used to mate the previous session's Holley 950-cfm carb to the Victor 454-R. The new power and torque curves were very flat: 687 lb-ft at 4,800 to 4,900 rpm and 703 hp from 6,200 to 6,400 rpm, a gain of 8.3 hp and 10.2 lb-ft.
Speed-O-Motive replaced the 950-cfm carb with its favorite dyno mule, a 1,050-cfm 4500 Dominator (Holley PN 0-8896-1) equipped with No. 81 jets, bolting it to a standard 1-inch open spacer. The larger carb at some rpm points gave away a few numbers below 4,000 but beyond that point was clearly superior to the 950-cfm carb. Average output from 2,500 to 6,500 rpm was now 545.1 lb-ft and 631.7 hp. At the peaks, the engine made 717 hp from 6,100 to 6,300 rpm, with 691 lb-ft on tap at 4,800. For the first time with the rectangular-port heads, peak and average torque production was within 1 lb-ft of the values obtained with the RPM Air-Gap dual-plane and rectangular-port heads or the Wilson-modded Victor Jr. oval-port intake and Race-Rite heads. However, the torque peak occurred some 500 rpm higher than with the oval-port combos.
The next step was to install the 1,050-cfm carb on the even larger Edelbrock Super Victor intake. This proved marginally superior, raising peak power production to 723 hp. The changes in average power as well as peak and average torque production were less than one number. At this point, we needed a bigger cam to fully realize the big intake's potential. As the saying goes, "Everything affects everything else."
Before piling on the huge Dominators, we had one last fling with the Holley 950-cfm 4150-style Ultra HP carb. Adapting the 950 to the Victor 454-R manifold's Dominator flange required a 2-inch-tall Edelbrock adapter (PN 8716). It was enough to push the engine over the 700hp mark.
Lunati 272/280 CAMOur quest for a bigger cam led us to a Lunati drag-race stick, grind No. RRB-308-316 (PN 50226LUN). This cam is pretty serious; from here on out, we'd be trading off torque and driveability for top-end power. The engine also liked 38 degrees of timing, where before it had been relatively timing-insensitive at 35 degrees. Running the BB-2 Plus heads with the new cam, the best overall runs were achieved using the Super Victor intake, the 1,050-cfm Dominator on a 2-inch spacer, and the large 21/8 headers. Below 3,000 rpm, there were now serious dips in torque output, although with a 540, dip is a relative term, as even at 3,000 rpm, output was still able to reach 545 lb-ft and 311 hp (compared with 594 lb-ft and 339 hp with the previous 255/263 cam). The torque peak rpm point increased 100 rpm (from 4,900 to 5,000), but more significantly, at the new peak, the torque output was only 664 lb-ft, a drop of 26 lb-ft. However, the torque drop was offset by a 31hp peak increase: 754 hp at 6,800 rpm, 500 rpm higher than the previous 723hp high. The engine was not happy under 3,000 rpm and in the 3,000-6,500-rpm range was still down by an average 24 lb-ft and 17 hp compared with the milder cam combo. Although this cam obviously isn't too street-happy, in a steeply geared lightweight car set up to keep the engine in a narrow higher rpm operating band, it should go down the track quicker.
The larger Super Victor (PN 2927) is specifically designed for 500ci-plus engines with high airflow requirements. With the 255/263 cam, it slightly bested the Victor 454-R but really came into its own with the two largest cams installed next.
BB-2 XTRA Heads, Comp 281/296 CAMA larger cam had helped; how 'bout even larger heads? On went Brodix's BB-2 Xtra castings, about the largest heads you can buy without raised intake ports or rolled-over valves, either of which requires expensive custom parts. Initial results were decidedly mixed. Once again, the motor preferred a 1-inch spacer. The bigger heads were down at the peaks by 6 hp and 3 lb-ft. The 661-lb-ft torque peak occurred 100 rpm higher, but the 748 max horsepower peak at 6,500 to 6,600 rpm was 200 rpm lower. The big heads were stronger from 3,400 to 4,800 rpm and 6,300 to 6,500 rpm, yet generally weaker at other rpm checkpoints. Still, the overall average difference in power and torque was less than one number. The Xtra heads still had uncut 119cc chambers, which cost us about a 1/2-point drop in static compression. In the 10:1 compression-ratio range on a large engine, we figured this could be worth 5-10 hp at most.
Perplexed, we took the Xtra and the Plus heads over to Westech Performance's flow bench, where again the results were decidedly mixed. Rat motor heads have two good and two bad intake runners. The so-called bad runners tend to direct the airflow to the side of cylinders 2, 3, 6, and 7; the good ports aim the charge more toward the center on cylinders 1, 4, 5, and 8. As seen in the table (page 92), the bad BB-2 Xtra runners outperformed the bad runners on the Plus heads only at 0.500-inch lift and higher; however, the good ports on the Xtra beat the Plus' good port from 0.200 inch up. Although not as significant as the intake side on a big-cam motor, the Plus exhaust port also flowed better over 0.300-inch lift.
ARP supplied all the fasteners, including special head-bolt sets for the aftermarket heads. Brodix BB-2 Plus and BB-2 Xtra heads require longer exhaust-side bolts due to the 0.600-inch-higher exhaust ports' taller bolt-boss columns (use ARP kit PN 135-3606). Otherwise, the heads accept all standard pistons, intakes, rocker arms, and guideplates.
Armed with the engine dyno and flow bench results, the experts said to make these heads work we'd need either really high static compression (more than 12:1) or a bigger cam-preferably both. Significantly raising the compression was not in the cards, as it requires a piston swap, but we could still jump up on cam timing, as the engine had some piston-to-valve clearance to spare.
Comp Cams lobe designer Billy Godbold recommended a drag-race cam with a 4/7 firing-order swap (1-8-7-3-6-5-4-2 instead of the stock 1-8-4-3-6-5-7-2). Originally used by some late-model production engines, the 4/7 swap has become common on high-rpm race engines as well. OEM engineers feel swapping the firing orders increases bottom-end durability and engine smoothness by better equalizing the bearing loads on the crankshaft. Many racers believe the 4/7 swap improves the sequence and location of the pulses in the intake, thereby cutting down on reversion. Depending on who you talk to, a 4/7 swap is worth anywhere from nothing to 10 hp.
Brodix says its BB-2 Xtra heads are for 540-582ci engines and need a minimum 13:1 compression. Oops-our 540 fell a little short in the CR department. BB-2 Xtra heads have 2.30/1.88 valves (compared with the BB-2 Plus' 2.25/1.88-inch combo). The Xtra's intake runner volume is listed at 365 cc, a whopping 53cc increase over the BB-2 Plus' 312cc runners.
The real benefits of this cam come from additional 0.050 duration: another 9 degrees intake and 16 degrees exhaust; not that the theoretical valve lift at zero lash was anything to sneeze at. At 0.824/0.800, it was up by 0.102 and 0.78 inch on the intake and exhaust, respectively. To go with its cam, Comp sent over a set of its new gold-aluminum-bodied roller rockers, a stud girdle, and Busch/SuperTruck-series valvesprings designed for maximum durability. Stouter springs are available for drag-only motors buzzing to eight grand, but they won't last as long.
Yeah, this cam really worked. Still, with the Super Victor, the Speed-O-Motive 1,050-cfm dyno-mule carb, and the engine's once again favored 2-inch open spacer, the new cam moved Godzilla up to 773 hp at 6,800, an increase of 25 hp. But it lost 15 lb-ft, with the torque not peaking until 5,800 rpm, 600 rpm higher than the Xtra heads with the Lunati grind.
Note the rounded tip on one of Comp's new 1.7:1 gold-aluminum roller rockers (arrow). It's designed to solve the interference problem with the top left valve cover bolt boss sometimes encountered with aftermarket heads. Comp includes two in every Rat rocker set. Previously, engine builders had to hand-grind aluminum rockers for clearance as needed.
Completing the valvetrain transformation to support the big cam was a Comp rocker-stud girdle. Offering increased high-rpm stability for the relatively heavy Rat motor valvetrain, a girdle is highly recommended for engines revving past 7,000 rpm with aluminum heads.
The Final Tune-upCould we find another 25 hp or so? You'll agree that 800 hp sure makes a good cover blurb. Reaching deep into its bag of tricks, Speed-O-Motive recommended a Dart single-plane intake and tricked-out Performance Carburetor Stage 4 1,050-cfm Dominator carb, a combination the company's had good luck with in the past. Again running a 2-inch spacer, a slight increase was observed, with 654 lb-ft at 5,500-5,600 rpm and 777 hp at 6,900.
Tightening the valve lash from the cam card's recommended 0.024-inch intake/0.028-inch exhaust by 0.010 inch to 0.014/ 0.018 was worth another 10 hp, bringing us to 787 hp at 7,000-7,100 rpm. Yikes-the engine wants an even larger cam! Moving up at this stage means fly-cutting the pistons for more valve clearance (but if we have to re-move the pistons, why not put in pop-ups to raise the compression?) and even stouter valvesprings (there was only 0.055 inch left until coil-bind). That's getting beyond the intent of a pump-gas engine. What else could we do?
Dart Machinery's single-plane intake was developed using sophisticated wet-flow technology. Although Dart says it's specifically designed for its own heads, it helped eke out another 10 hp when used with a generic 2-inch open spacer that did not even match the hump in its cloverleaf-shaped carb-mounting flange.
How 'bout mill the heads 0.030 inch to restore that missing 1/2-point of static compression? It proved to be worth some low- and midrange torque; the engine gained 8.0 lb-ft at the peaks and 6.5 lb-ft and 6.5 hp in overall average. However, peak horsepower declined slightly to 785 hp at 6,900-7,000 rpm. Go figure.
Last but not least, Speed-O-Motive's Ricky Caven played around with the carburetor calibration and increased the timing from the 38 degrees we'd been running this test session all the way to 42 degrees. That brought us to 659 lb-ft at 5,600 and 5,800 rpm. But even better, it garnered us another 8 hp, finally bringing the engine to 793 hp at 7,000 rpm. And that's all she wrote, boys. Short of some major parts changes, that's as good as it gets: 7 hp short of our 800hp goal, but not bad on a normally aspirated, 10.67:1 engine running 91-octane gas.
How far we've comeIt's been a long climb from the original baseline configuration using GM production oval-port heads and a flat-tappet hydraulic cam. After starting out with only 576 lb-ft and 480 hp, over the course of three months of testing we have clawed our way to 659 lb-ft and 793 hp with the big Comp roller cam, Brodix BB-2 Xtra heads, a 4500 Dominator carb, and a Dart intake. We did all this with an engine with less than 11:1 compression running on 91-octane California unleaded straight out of the pump. In the process, playing with a giant-size engine like this 540 has only reaffirmed the old homily, "There's no replacement for displacement." Or, to steal a line from the last Godzilla movie, this project's namesake, "Size does matter." Parts too big for a classic 427/454 Rat motor were tamed like a henpecked spouse. Forget about 13/4- or 17/8-inch headers. Don't start with anything less than a 950-cfm carburetor. Consider 12:1 compression with the larger aluminum heads-even on pump gas, our big head/big cam combo was cranking at just 170 psi with the largest cam and liked 42 degrees of lead. And the fact that the engine responded to tighter-than-recommended lash settings even with a 281/296 (at 0.050) cam indicates it still needs even more in that department.
In its final (to date) 790hp configuration, this engine is capable of propelling a 3,000-pound car with a professional-level chassis into the 8.90s at 150-plus mph. But if I had to pick one all-round best combo out of this entire marathon, one that is equally at home on the street or at the strip, it would be the 694hp/694-lb-ft mid-level combo where the engine was equipped with Brodix Race-Rite oval-port heads, the Lunati solid roller Voodoo cam with 255/263 duration at 0.050, Hooker headers with 2-inch primaries by 31/2-inch collectors, and the Holley 950-cfm Ultra HP carburetor atop the Wilson-modified Edelbrock Victor Jr. intake. This combo ran well from 2,500 to 6,500 rpm, producing 694 lb-ft at 4,800 and 694 hp at 5,800 rpm. It averaged more than 633 lb-ft and nearly 543 hp through the overall curve. This kind of output is still enough to drive our proverbial 3,000-pound car to a potential 9.30-second, 144-mph quarter-mile e.t. Back in the '70s, that was Pro Stock territory-now it's the ultimate street/strip Godzilla terror
The Super Victor intake, 1-inch open spacer, 1,050-cfm Holley carb, Brodix BB-2 Plus heads, and Lunati solid roller cam with 255/263 degrees duration at 0.050 pushed the 540 to 723 hp. The engine no longer seemed to be intake-limited-it was now cam-limited.
Moving up to Lunati's 272/280-degree-duration (at 0.050) solid roller cam kind of represents the point of no return. There is no longer any pretense of street driveability. It was only from 5,800 rpm on up that torque and power output exceeded the previous combination. But with a 2-inch spacer and a Super Victor, the engine crested 750 hp.
Here's another great leap forward in cam radicalness: Comp's big Comp Eliminator drag-race roller cam jacked output to nearly 775 hp. The engine wasn't happy on the dyno below 3,300 but now ran easily through 7,300. If you have to ask, average output from 3,300 to 6,500 was down about 18 lb-ft and 12 hp.
Bolting on a Dart intake, swapping carbs, playing with the valve lash and timing, and milling the heads pushed the engine-now with more than 300 pulls on it-to 793 hp and 657 lb-ft. At this point, it really wants even more cam and higher compression.
MECHANICAL ROLLER CAMSHAFT SPECIFICATIONS All values are in crankshaft degrees unless otherwise noted (except for lobe-separation angle, which is in camshaft degrees). Some totals may not add up due to rounding. MAKE PART NO. GRIND LIFT (INCHES) BASELINE VALVE LASH ADVERTISED DURATION CAM TIMING AT 0.050-INCH TAPPET LIFT LOBE CENTERLINE LSA At Tappet At Valve (Zero Lash) Duration Intake Exhaust Intake Exhaust Rocker Ratio Intake Exhaust Intake Exhaust Intake Exhaust Intake Exhaust Opens Closes Opens Closes Intake Exhaust Lunati Cams 60234 VBC-295 0.400 0.400 1.70:1 0.680 0.680 0.018 0.018 285 293 255 263 23.5 BTDC 51.5 ABDC 67.5 BBDC 15.5 ATDC 104 116 110 50226 RRB-308-316 0.425 0.425 1.70:1 0.722 0.722 0.028 0.030 308 316 272 280 28 BTDC 64 ABDC 72 BBDC 28 ATDC 108 112 110 Comp Cams 11-751-14 CB 47S 314RXD-14 0.485 0.471 1.70:1 0.824 0.800 0.024 0.028 314 334 281 296 28 BTDC 72 ABDC 84 BBDC 32 ATDC 114 114 114 VALVESPRING DATA Unless otherwise noted, all numerical values are in linear inches. MAKE PART NO. TYPE USED WITH ID x OD RATE SEAT PRESSURE OPEN PRESSURE COIL-BIND Comp Cams 991-16 Dual w/damper Lunati 60234 solid roller cam 0.783 x 1.639 640 lb/in 182 lbs @ 2.00 630 lbs @ 1.{{{300}}} 1.125 Lunati Cams 74660LUN Dual w/damper Lunati 50226 solid roller cam 0.764 x 1.620 636 lb/in 230 lbs @ 1.95 675 lbs @ 1.250 1.110 Comp Cams 26099-16 Dual w/damper Comp 11-751-14 solid roller cam 0.769 x 1.625 561 lb/in 245 lbs @ 2.050 693 lbs @ 1.250 1.184 BRODIX BB-2 PLUS VS. BB-2 XTRA Airflow in cfm at 28 inches of water BB-2 PLUS BB-2 XTRA LIFT GOOD BAD GOOD BAD (IN.) INTAKE INTAKE EXHAUST INTAKE INTAKE EXHAUST 0.050 32.5 36 25.8 34.2 27.2 26.1 0.{{{100}}} 69.5 73 60 69 {{{62}}}.6 69.3 0.{{{200}}} 146 149 120 154 145 121 0.300 218 220 162 223 209 154 0.400 276 274 195 283 265 187 0.500 315 306 223 328 310 211 0.{{{600}}} 346 326 245 361 333 231 0.700 360 335 258 372 352 245 0.800 355 340 270 368 363 260 540 GODZILLA PHASE 3 PARTS LIST These are the major parts used on the 540 during the Phase 3 test session. All dimensions are in linear inches unless otherwise noted. MANUFACTURER PART TYPE DESCRIPTION/NOTES PART NO. AMT. COMMON PARTS APPLICABLE TO ALL PHASE 3 TESTS For engine assembly and valvetrain parts not listed here, see HOT ROD, May ’08, “Godzilla Rat,” page 108 — Carb spacer Generic 1-inch open spacer, 4500 Dominator flange (as required) Generic 1 — Carb spacer Generic 2-inch open spacer, 4500 Dominator flange (as required) Generic 1 ARP Head-bolt kit High-performance series, hex-head, Brodix aluminum heads w/raised exhaust ports 135-3606 1 Comp Cams Lifters Mechanical roller lifter, 0.{{{300}}} taller body (tall body required w/Dart block) 883-16 1 set Fel-Pro Header gasket 1.94 round ports, perforated steel core w/antistick coating 1411 1 Fel-Pro Intake gasket Composite w/coating, rectangular port, 1.82 x 2.54 x 0.060, no upper bolt holes 1275 1 Hooker Exhaust headers Super Comp, 21/8 x 30-38 primaries, 3½ x 12 collectors, ’67-’69 {{{Camaro}}} 2386-1HRK 1 Manley Pushrods 4130 chrome-moly, swaged end, intake, 3/8-od x 8.{{{200}}} OL 25820-8 1 set Manley Pushrods 4130 chrome-moly, swaged end, exhaust, 3/8-od x 9.{{{100}}} OL 25910-8 1 set APPLICATION-SPECIFIC PARTS: BRODIX BB-2 PLUS RECTANGULAR-PORT HEADS Brodix Cylinder head BB-2 Plus, 312cc intake runner, 119cc chamber (milled to 112 cc, see text) 2021014* 2 Edelbrock Carb adapter 4500 carb intake-flange-to-4150 carb flange, 2-inch, open 8716 1 Edelbrock Intake manifold Single-plane, Dominator flange, Super Victor big-block Chevy 2927 1 Edelbrock Intake manifold Single-plane, Dominator-flange, Victor 454-R 2907 1 Holley Carburetor 4150 HP Ultra, 950 cfm, mechanical secondaries, gasoline 0-80676 1 Holley Carburetor 4500 Dominator HP, 1,050 cfm, mechanical secondaries, three-circuit metering 0-8896-1 1 APPLICATION-SPECIFIC PARTS: BRODIX BB-2 XTRA RECTANGULAR-PORT HEADS Brodix Cylinder head BB-2 Xtra, 365cc intake runner, 119cc chamber (milled to 112 cc, see text) 2021038* 2 Dart Machinery Intake manifold Single-plane, Dominator flange 41124000 1 Edelbrock Intake manifold Single-plane, Dominator flange, Super Victor big-block Chevy 2927 1 Holley Carburetor 4500 Dominator HP, 1,050 cfm, mechanical secondaries, three-circuit metering 0-8896-1 1 Performance Carburetors Carburetor PC 4500, Stage 4, 1,050 cfm, mechanical secondaries, three-circuit metering PC4DOM1050 1 APPLICATION-SPECIFIC PARTS: LUNATI MECHANICAL ROLLER CAM PN 50226 Lunati Cams Camshaft Mechanical roller, 272/280 degrees at 0.050 50226LUN 1 Lunati Cams Retainer 10-degree titanium, for 74660LUN spring and mechanical roller cam 76110LUN 1 set Lunati Cams Valve lock 10-degree, 11/32 valve stem, chrome-moly steel, w/lash cap recess (16 per package) 77111LUN 2 sets Lunati Cams Valvespring Ultra series, dual w/damper, 636 lb/in rate 74660LUN 1 set APPLICATION-SPECIFIC PARTS: LUNATI MECHANICAL ROLLER CAM PN 50226 Lunati Cams Camshaft Mechanical roller, 272/280 degrees at 0.050 50226LUN 1 Lunati Cams Retainer 10-degree titanium, for 74660LUN spring and mechanical roller cam 76110LUN 1 set Lunati Cams Valve lock 10-degree, 11/32 valve stem, chrome-moly steel, w/lash cap recess (16 per package) 77111LUN 2 sets Lunati Cams Valvespring Ultra series, dual w/damper, 636 lb/in rate 74660LUN 1 set APPLICATION-SPECIFIC PARTS: COMP MECHANICAL ROLLER CAM PN 11-751-14 Comp Cams Camshaft Mechanical roller, 281/296 degrees at 0.050 11-751-14 1 Comp Cams Distributor gear Polymer composite material, 0.500 shaft (MSD), compatible w/all cam materials 12140 1 Comp Cams Retainer 10-degree titanium, for 26099-16 spring and mechanical roller cam 733-16 1 set Comp Cams Rocker arm Ultra-Gold series, aluminum full-roller, 7/16-stud, 1.70:1 ratio 19021-16 1 set Comp Cams Stud girdle kit Solid-bar design, standard rocker stud spacing, fits Brodix-2 heads 4021 1 Comp Cams Valve lock 10-degree, 11/32 valve stem, titanium, w/lash cap recess 638-16 2 sets Comp Cams Valvespring Elite race series, dual w/damper, 693 lb/in rate 26099-16 1 set MSD Distributor gear Bronze material, 0.500 distributor shaft (MSD), compatible w/billet steel cams 8471 1*Part numbers vary per options; see manufacturer's Web site.
540 GODZILLA PROJECT TEST HIGHLIGHTS All Phase 1 tests below are corrected to SAE J1349 net power and torque ratings, which is more representative of a real-world street driver. Phase 2 and 3 tests are corrected to SAE J607 gross hot rod correction factor. There is approximately a 5-7 percent difference between the two. PHASE 1/MAY ’08 TORQUE (LB-FT @ RPM) POWER (HP @ RPM) CYLINDER HEADS CAMSHAFT CARBURETOR INTAKE MANIFOLD HEADERS 576.2 @ 3,{{{600}}} 480.5 hp @ 5,{{{200}}} GM large oval-port iron Lunati Voodoo, hydraulic flat-tappet, 233/241 @ 0.050, 0.554/0.572 lift Holley HP 750-cfm double-pumper Edelbrock Performer 2-O, 1-inch spacer Hooker 2 x 3½ 602.6 @ 3,800 515.3 @ 5,200 Same as above Lunati Voodoo, hydraulic roller, 231/239 @ 0.050, 0.600/0.600 lift Holley HP Ultra 950-cfm double-pumper Same as above Same as above 611.9 @ 4,{{{100}}} 542.4 @ 5,{{{300}}} Same as above Same as above Same as above Edelbrock Victor Jr. 454 2-O, 1-inch spacer Same as above 614.6 @ 4,000 535.8 @ 5,200-5,400 Same as above Same as above Same as above Edelbrock RPM Air-Gap 2-O, 1-inch spacer Same as above 665.3 @ 4,200 604.4 @ 5,300 Brodix Race-Rite oval-port aluminum Same as above Same as above Same as above Same as above PHASE 2/JULY 695.6 @ 4,{{{100}}} 627.1 @ 5,400 Same as above Same as above Same as above Same as above Same as above 683.1 @ 4,100 637.5 @ 5,500 Same as above Same as above Same as above Edelbrock Victor Jr. 454 2-O, 1-inch spacer Same as above 686.4 @ 4,{{{200}}} 555.6 @ 5,{{{600}}} Same as above Same as above Same as above Wilson Manifolds–modified Victor Jr. 454 2-O, Wilson tapered 1-inch spacer Hooker 21/8 x 3½ 699.4@ 4,{{{300}}} 671.3 @ 5,700 Same as above Lunati Voodoo, solid roller, 255/263 @ 0.050, 0.680/0.680 lift Same as above Edelbrock RPM Air-Gap 2-O, 1-inch spacer Hooker 2 x 3½ 684.3 @ 4,500-4,600 and 4,800-4,{{{900}}} 679.4 @ 5,600 Same as above Same as above Same as above Edelbrock Victor Jr. 454 2-O, 1-inch spacer Hooker 21/8 x 3½ 694.3 @ 4,800 693.6 @ 5,800 Same as above Same as above Same as above Wilson Manifolds–modified Victor Jr. 454 2-O, Wilson tapered 1-inch spacer Hooker 2 x 3½ 691.2 @ 4,200-4,300 678.2 @ 5,800 Brodix BB-2 Plus rectangular port, 112cc chamber, 312cc intake runner Same as above Same as above Edelbrock RPM Air-Gap 2-R, 1-inch spacer Same as above 684.6 @ 4,800 690.5 @ 6,200 Same as above Same as above Same as above Same as above Same as above 676.8 @ 4,900 694.7 @ 6,200 Same as above Same as above Same as above Same as above Hooker 21/8 x 3½ PHASE 3/SEPT. (THIS ISSUE) 687 @ 4,800-4,{{{900}}} 703 @ 6,{{{200}}}-6,400 Same as above Same as above Same as above Edelbrock Victor 454-R, 2-inch spacer/adapter Same as above 691 @ 4,800 717 @ 6,{{{100}}}- 6,{{{300}}} Same as above Same as above Holley 4500 HP 1,050 cfm Edelbrock Victor 454-R, 1-inch spacer Same as above 690 @ 4,900 723 @ 6,300 Same as above Same as above Same as above Edelbrock Super Victor BBC, 1-inch spacer Same as above 664 @ 5,100 754 @ 6,800 Same as above Lunati solid roller, 272/280 @ 0.050, 0.722/0.722 lift Same as above Edelbrock Super Victor BBC, 2-inch spacer Same as above 661 @ 5,200 748 @ 6,500-6,{{{600}}} Brodix BB-2 Xtra rectangular port, 119cc chamber, 365cc intake runner Same as above Same as above Edelbrock Super Victor BBC, 1-inch spacer Same as above 646 @ 5,800 773 @ 6,800 Same as above Comp Cams solid roller, 4/7 swap, 281/296 @ 0.050, 0.824/0.800 lift Same as above Edelbrock Super Victor BBC, 2-inch spacer Same as above 654 @ 5,500-5,600 777 @ 6,900 Same as above Same as above PC Stage 4 4500 1,050 cfm Dart single-plane Same as above 649 @ 5,700 787 @ 7,000- 7,100 Same as above As above, but tight-lashed to 0.014/0.018 Same as above Same as above Same as above 657 @ 5,600-5,700 785 @ 6,900- 7,000 As above, but milled chambers to 112 cc Same as above Same as above Same as above Same as above 659 @ 5,600-5,800 793 @ 7,000 Same as above Same as above but total ignition advance increased from 38 to 42 degrees