The stroker crankshaft is from Mopar performance (PN P5007252), and has had the journals machined down from 2.25 to 2.00 inch to match a common Chevy small-block size. Mike found an excellent deal on a set of GRP alloy rods with that dimension, and since that size offers so many bearing choices, they decided to go with it. At 6.46-inch in length, the rods are quite long. Even with the 4-inch stroker crank, the roomy crankcase eliminates the need for any grinding for clearance. ACL bearings with a calico coating were used throughout. Pro-Gram steel billet caps are used to help keep the high-winding engine together. The cylinders were bored over-sized and finish-honed to a final dimension of 4.125-inches, yielding a final 427ci displacement. The plateau wall finish is similar to a traditional mirror finish, with a residual super-fine crosshatch that knocks off microscopic high spots and ensures an excellent ring seal.
A parts connection in New Mexico turned up a mint set of W-8 aluminum cylinder heads left over from the NASCAR Craftsman Truck series, complete with Manley titanium valves with 2.150-inch intake and 1.65-inch exhaust valves. The heads were privy to a full five-axis CNC porting by Chapman Porting Service in Salt Lake City. Also included was a complete Jesel valvetrain setup. Valve seat angles are, as Don puts it, "pretty much a full radius with a 45-degree angle in there somewhere."
A consultation with Chris Mays of Competition Cams yielded a promising profile, carrying PN CRS1844/4082 R108.0. It's a roller grind with .739-inch lift on the intakes and .704-inch lift on the exhaust lobes. The duration is 282 degrees on the intakes and 280 degrees on the exhaust at .050-inch. Lobe separation is 108 degrees, but the cam was installed at 104 degrees to help the bottom end. (This will probably be changed... more about that later). It's important to note this is not an extremely radical grind, but rather a practical bracket cam designed for consistent performance and repeatability.
There were no factory lifters available for the block, and nothing from the aftermarket was available with the exception of some high-end units that cost $125 apiece. They were top-notch, but just did not fit into the budget. After consultations with Dave Crower of Crower Cams, it was determined that a variation of their lifters for a NASCAR SB-2 small-block Chevy with a diameter of .904, as opposed to the NASCAR Chevy's .875, would work with a little adaptation. Namely, the tops of the lifter bore bosses had to be machined down about a quarter-inch, so the link bar between the lifters would clear the block. High-tech Comp Cams pushrods with through-the-center oiling are used.
Don machined a custom valley cover for the engine, as none was available either from the factory or in the aftermarket. The block has no provision for a water pump, so a Meziere pump was fitted to the lower radiator hose to handle the coolant pumping chores.
It was also up to Don to build his own oil pan. He dubbed it the "origami oil pan" after the Oriental art of folding paper because that's the way he designed it-with paper templates and a lot folding. It was fabricated from a single piece of aluminum to minimize the amount of seams that required welding. Once his cardboard oil pan fit properly, Don recreated it in aluminum. A beefy external oil pump by Peterson Fluid Systems ensures adequate lubrication flow for the high-winding small-block.
After much research, a potential problem was pinned down at the diameter of the holes that limit the amount of oil delivered to the lifter galley. The strength of the oil pump was such that it evacuated virtually all the oil from the bottom end at high rpm. This would leave insufficient lubrication for the crank, rods, and cylinders. Once the hole size was reduced to the correct diameter, the problem was averted. An ATI harmonic balancer was used, both for its rebuildable features, as well as its lighter weight.