Crankcases were from a street bike, with the cylinder
base areas welded to accept special early H2R cylinders with altered stud
Those cylinders were also very special, cast in their standard positions, with the outer cyls having inside aimed exhaust ports, directly opposite the stock street bike cyls. They were also fully bridged on inlet and exhaust ports. Why the studs moved? Well. moving the studs both side to side and front to back farther apart, allowed for a larger transfer port, front to back.
Those cylinders also had the nice Husqvarna dropped style exhaust ports, the ones that worked the best, and with the altered stud pattern, wider inlet and exhaust ports as well as the bridging.
The heads also were special cast, both to match the shorter cylinder fins on the sides and for the altered stud pattern.
Carbs were H1R 35mm Mikunis, H1R and special H2R ignitions were used, along with three new transmission ratio packs over the original 3 H1R sets the factory had available for race team tuners/riders.
The story on how we were made to run street cylinders with no bridged ports. Our race team boss, Bob Hansen, also vice -president of the AMA back then, noticed the Suzuki TR750's had just two head studs that were moved form the stockers, and got a protest of Jody Nicholas's bike at one fo the races, but keeping typical Bob, quiet about the Kawasaki altered everything. The AMA came out with a stock cylinders and heads rule, and the Suzukis just used radically ported and worked street bike cylinders and heads, we did as well, having to switch the cylinders R to L, and obliterate the cooling fins off the outer sides so they'd change over.
If the cylinders on that bike were done by the U.S. race team person I think they were, and not revised by Randy Hall later, both they, and the heads are simply priceless, and possibly the fastest set still in existence.