Motor And Drivetrain
Though he knew that the fat-block would add more weight to the front of the car than a small-block or an all-aluminum LS type, Herb couldn't resist temptation-another test of skill to make the car handle and brake like squadrons of lighter fighters with better weight distribution. Kind of like bringing an M2 .50-cal to a 9mm shootout. To make his boss bark, he sent the Mark IV 454 iron block to B&B Machine in Leesburg, Virginia. The cylinders were relieved of 0.060-inch (now 4.310-inch bore) and kept the stock 4.00-inch stroke. Scat delivered a balanced Pro Comp Lightweight 4340 crank and 6.385-inch 4340 H-beam connecting rods with ARP 7/16-inch fasteners to mate up with a set of SRP 10.2:1 pistons replete with ceramic-coated tops and dry-film lubricant on the skirts. The ring packs are from Total Seal, and the main and rod bearing shells received dry-film lube as well. Herb stuffed the short-block with a Comp Cams hydraulic roller (0.612-inch lift, 244 degrees duration at 0.050), Schubeck Racing Roller X ceramic lifters, and a Cloyes double-roller timing set. Oiling is handled by a Milodon road race pan and Moroso blueprinted race pump. The AFR 305 Magnum heads are untouched and sport 2.250- and 1.880-inch stainless steel valves and pass 363 cfm on the intakes at 0.600-inch lift. The heads are equipped with AFR titanium retainers and valvesprings, Jesel Sportsman shaft rockers (1.7:1), and Jesel 3/8-inch diameter chrome-moly pushrods. For the induction system, Herb veered from the usual and invested in an Edelbrock Victor Jr. EFI intake manifold crowned by a Mass-Flo 1,000-cfm throttle body sucking through a free-flowing K&N element. A Mallory sparker shoots juice through Performance Distributors Livewires and timing is 14 degrees BTDC. Junior Stock pioneer Jere Stahl, still going strong in York, Pennsylvania, stepped the exhaust extractors with 2.00-inch-to-2.25-inch primaries and merged them with 3.5-inch collectors. From there, the mixture enters a Dr. Gas 3.5-inch cross-pipe and on to Spin Tech mufflers sprouting 4.0x2.5-inch side-exit pipes. Accessories, save for the Meziere water pump, are connected by a Jones Racing Products radius-tooth drive system. For track days dominated by the Heat Beast, Herb added a Performance Rod & Custom extreme-duty oil cooler in conjunction with a Hamburger remote oil filter mount and block adapter. He used ARP fasteners throughout. Dynamometer output is 619 hp at 6,200 rpm and 570 lb-ft of torque at 4,800 rpm which makes for a good low-rpm response and a little extra steam on the top end (163.50 mph at Maxton). Torque is ordered to the rearend via a McLeod Street Twin dual-disc clutch assembly, a Tremec TKO600 RR (2.87, 1.89, 1.28, 1.00, 0.82:1), and an Inland Empire 4-inch diameter aluminum driveshaft. The end game is a Currie 9+ axle fitted with a Detroit True Trac differential and 3.70:1 gears. For Maxton runs, there's another pumpkin housing with 3.30:1 gears.