Jeff Kettman: "In addition to the LSX block, GMPP offers a wide variety of Mouse and Rat motor blocks originally developed for racing. All the various Bowtie, Race, and Sportsman small-blocks that are offered by GM Racing were originally developed, tested, validated, and used in GM racing programs. For example, all the Bowtie blocks (1248xxxx part #) are based off the same casting that was used for our NASCAR engines when teams ran 18-degree cylinder heads. Then we moved on to the SB2.2 engines, and those blocks are now available as well. The ROx block was actually the first generation of the RO7 block that is now used in NASCAR. Of course, all the small-blocks ended up in use in many other forms of racing such as in NHRA, IMSA, Trans-Am, and SCORE.
"The Bowtie big-blocks were developed for Pro Stock drag racing and we now also offer DRCE blocks, which are a very specialized big-block used in today's Pro Stock cars. The ZL1 block is a different story. Most everybody is familiar with its history from the '60s and early '70s. What happened was that some GM race engineers were reviewing the list of tooling when Winter's foundry-who cast the original ZL1 block-was shutting down. Being gearheads, they recognized that some of the part numbers were for the ZL1 block tooling. Since the ZL1 was a quasi race engine to begin with, and it was produced in low volumes, it made sense for GM to reacquire the tooling. We refurbished it, brought it back to the market, and you can still buy an aluminum block 427 big-block."
Full Race Blocks
Jeff Kettman: "Two very interesting small-block Chevy blocks that GMPP offers are an 8.325-inch short-deck unit as well as a block with 283 mains. In an era when hot rodders want the tallest deck and max displacement possible, this might seem odd, but keep in mind that they were developed for very specific racing applications. The short-deck blocks were originally developed for Trans-Am racing where the displacement limit was 310 ci. In order to keep weight to a minimum and optimize the bore/stroke ratio, the GM Racing engineers came up with the short-deck engine. We also offer an 8.700-inch medium-deck blocks, which were designed for the NHRA Pro Stock Truck program. The 283-sized mains on these blocks came about as race engine builders looked for every advantage possible to make more horsepower. They determined that the smaller mains had less friction and therefore made more power. With today's engineering tools like FEA, they were able to see that the smaller main crankshafts could handle the loads with the smaller mains, and they could also get the added benefit of a lighter crankshaft."