Bill would absolutely have shat his briefs for the 572 under that Yenko Stinger hood, because the biggest thing available in the day was 494 inches, which was based on an aluminum Can-Am cylinder block. The Jenkins/Smeding project grows out of a Dart Big M cylinder case with a 4.630-inch bore. Into those sacred holes, Smeding poured tight-fitting, high-silicone content-forged pistons that have cooling trusses on their underside. The Jenkins-prescribed mini-dome is marked for a 10.2:1 compression ratio (the GMPP 620hp 572 crate operates on 9.6:1) and installed at zero-deck height for maximum combustion quench. The ring pack features a moly-faced ductile iron 0.043-inch top, a reverse taper 0.004-inch second, and a stainless steel light-tension 3/16-inch oiler. Pistons come to the connecting rods with full-floating wrist pins. The rods are 4340 steel H-beams and fitted with bronze pin bushings.
The rod bolts are 7/16-inch diameter and rated at 190,000 psi. They're attached to the micro-polished and chamfered journals on a forged arm that cranks up a 4.250-inch stroke. For lightness, the number one and four crank pins are hollow. Bearing surfaces have a nitride treatment and the unit is internally balanced. For oiling, Smeding uses a windage tray under the 7-quart pan with a full kick out on the passenger side to help sling oil away from the crank.
When those pistons rocket northward, they are challenged by aluminum cylinder heads carrying 2.30/1.88 stainless valves that nestle down in five-angle seats in 120cc combustion chambers. The ports are CNC-prepped, and the intakes flow a 335-cfm volume at peak-all the better for the custom-ground COMP hydraulic cam. It opens wide, 0.699-inch on the intakes and 0.666-inch on the exhaust side. As Bill no doubt advised, Smeding keeps duration and lobe-center specs to himself. On top of the head, aluminum roller rocker arms working on extra large trunnions hump at a ratio of 1.7:1.
Smeding capped the volcano with an Edelbrock single-plane Victor intake manifold hosting a 4510 series 1,050-cfm carburetor as calibrated by Quick Fuel Technologies. Fire shoots from a modified HEI distributor to ACDelco spark plugs, and the trash resultant is sucked away by Lemons' ceramic-coated custom headers equipped with 21/2-inch primary pipes and 4-inch collectors. The remainder of the system is 3-inch stainless steel interrupted slightly by minimal but mellow Magnaflow mufflers. Ancillaries include a PRC aluminum radiator/support and March billet aluminum accessory drive that includes a Vintage Air Gen IV A/C compressor and a Power Master 140-amp alternator. The whole schmear is topped by an engine cover custom built by Lakeside and incorporates a K&N filter element.
As a balls-out cruiser, the engine absolutely feasts on an overdriven top gear as found in the Gearstar Level 5 4L85E (2.42:1 low, 0.75:1 top gear) transmission. It's under the influence of a GMPP controller and is fitted with an 11-inch Yank converter, a Cheetah Tranz brake system, and a custom billet pan. Leisinger changes up with a B&M Street Bandit shifter. To get the grunt to the blacktop, Drive Line Services in Sioux Falls, South Dakota, spun up a custom aluminum prop shaft. With 4.10s in the third member, the hefty transmission provides a realistic 3.00:1 cruise gear for the 850hp/840 lb-ft Rat.
In another sphere, the body was taking shape. To achieve the key to the visual impact the Camaro provides, Lakeside frenched the front and rear bumpers (painted silver), shaved the drip rails, installed '68 doors (to omit the vent windows), removed the outside mirrors, recessed the taillights with Marquez LED billet pieces, molded the spoiler into the trunk and rear quarters, deleted the window moldings, and brought the glass out almost flush with the body. The result is a sleek envelope that appears longer and lower than it really is.