There's more to the performance world than buzz-box small-blocks that putt around town. For the true street heroes that dream of big-time power, the easiest way to get there is with major league cubic inches. That means big-blocks. We canvassed the big-block world and came up with seven engines, from Mopar 440s to Ford 460s, through Buick, Pontiac, and Olds 455s, a 500ci Cadillac, and of course, a 454ci big-block Chevy.
We had a simple plan come up with a power combination for each one of these seven engines that would make a minimum of 500 hp and 500 lb-ft of torque. We will detail the carb, intake, heads, cam, compression, and exhaust components you would need to duplicate this level of power from each engine. Our goal was the mildest and least expensive combination that would make this power so that these engines could easily run on pump gas while prowling the neighborhood looking for unsuspecting prey.
So dive right into your favorite engine, but we'd suggest reading all of the engine combos. No tellin' what you might learn about these different engines and what it takes to be a 500hp Street Hero!
Pontiac 455
"Five hundred horsepower? It's like falling off a log." That's how Ken Crocie from HO Enterprises described making five big ones with a pump gas 455 Pontiac. Crocie recommends not bothering with the stock Pontiac heads. He says that by the time you're done rebuilding and porting the stock iron castings, you will have invested almost as much as a set of the Edelbrock aluminum castings.
For a camshaft, Crocie recommends one of his own hydraulic flat-tappet dual-pattern cams that specs out with 234/242 degrees of duration at 0.050-inch tappet lift with 0.470/0.485-inch valve lift and a lobe separation angle of 112 degrees. With a compression ratio of 10.2:1, Crocie says this should be a very streetable combination that would be on the ragged edge of compatible with pump gas only because the shorter cam will make more midrange cylinder pressure. Crocie has seen an 80hp jump over stock Poncho castings with the Edelbrock alloy heads.
On the induction side, Crocie heartily recommends an Edelbrock RPM intake, and he prefers the Edelbrock RPM 850-cfm Q-jet but reports that a similar-sized Holley or Demon would also work very well. On the exhaust side, Crocie notes the Doug Thorley 13/4-inch headers fit the A-body GTO very well, and he'd match it up with a complete 3-inch exhaust system. This will make an easy 500 hp, and the last engine he built like this made 519 hp at 5,800 and 560 lb-ft of torque at an amazingly low 3,900 rpm. The weak links in the Pontiac 455 are the cast-iron connecting rods. If you're building a fresh engine, Crocie warns under no circumstances should you reuse the stock cast rods. Both Scat and Eagle make 4340 forged steel rods that are an excellent choice for reliability and price.
Specs
•Displacement: 455ci, bore x stroke--4.151x4.210
•Carburetor: 850-cfm Edelbrock Performer RPM Q-jet, PN 1910
•Intake: Edelbrock Performer RPM Pontiac, PN 7156
•Heads: Edelbrock Performer Pontiac, 87cc chamber 2.11/1.66-inch valves, PN 60579 complete
•Compression: 10.2:1
•Camshaft: HO hydraulic flat-tappet cam, PN HC02, 294/302 adv., 234/242
•degrees @ 0.050, 0.470-/0.485-inch lift 112-degree lobe separation
•Headers: Doug Thorley 13/4-inch primary pipe
•Exhaust: 3-inch exhaust with DynoMax mufflers