It's a generally accepted fact that no one region in the country has a monopoly on drag racing ingenuity. Colorado, though better known for its skiing and beautiful mountain scenery, has also produced some outstanding Mopar racers. Master machinist Don Hackenberg is among them. In his heyday, he was a major player in NHRA's Modified Production ranks. Now in his mid-sixties and semi-retired, Don's skills and competitive instincts are alive and well. so when a certain special Chrysler aluminum small-block came into his possession, the wheels began to turn.
Enter racer Mike Molgard. Don and Mike had collaborated on an earlier small-block Mopar engine project, and when Mike walked into the shop and saw the block, he began asking questions. The two of them put their heads together and decided they were looking at the basis for a perfect drag racing engine. The result is a hybrid that's part circle track, part drag racing, and all small-block Mopar. Arguably one of the more unusual Mopar drag race engines we've seen to date.
Don's home-based shop houses a lot more sophisticated machinery than one would expect and is a perfect match for the car for which the engine was destined. Mike's turquoise '65 Belvedere looks for all the world like a 14-second street/bracket car. It's all steel, sporting the full factory interior including the back seat, and the battery is still in the front. In that configuration, it ran a 10.54 quarter-mile e.t. with a 395-inch cast-iron small-block, eliciting lots of puzzled looks from spectators in the pits. For a while, Mike considered a big-block, but the decision was made to stay with a small-block. It would be a pioneering effort, but the result would be totally unique, offering a level of performance normally only available from a big-block.
The block casting is genuine Mopar (PN 4532711), but there most of the similarities end. For one thing, it's all aluminum and even the most basic accessories, such as the front timing cover and oil pan, had to be custom fabricated. Even some basic technical aspects of the oiling system had to be worked out, which proved to be more challenging than expected. At one point, Don cranked up his machines and built his own distributor from scratch out of a solid piece of billet aluminum. Try that sometime in your home workshop!
The history of the block is interesting in itself. Although fabricated of light weight aluminum alloy, it was judged too heavy by the World of Outlaws circle track racers for whom it was designed and was scrapped by Chrysler in favor of a lighter casting. The source of the heaviness can be attributed to the fact it was designed like a smaller version of a Top Fuel block, replete with all sorts of reinforcing ribs. Many insiders on the circle track circuit maintain it's a better block than the one they now use. Among other heavy-duty features, it is a windage block featuring a kick-out on the passenger side to divert oil from the crankshaft, thus reducing parasitic horsepower loss.
A high-rpm aluminum race engine requires durable components. Lightweight (440 gram) CP aluminum-alloy pistons were used because of excellent quality, and can tolerate a fairly tight .0045-inch piston-to-wall clearance. The rings used are .043-inch in the top and .043-inch in the second groove in conjunction with 3mm low-tension oil rings. "Drag-wise, it's like having no rings at all when there's no compression on the top ring," said Don. Pistons are gas-ported to provide maximum ring seal when it is most needed. The compression ratio, at about 13.8 to 1, is fairly conservative by today's race engine standards.