I never lightened gears in one but never saw a need to. To lighten 30% is a lot. Which means big holes and I would be afraid that would make them weak if your trying to pound them with a good bit of horsepower.
Any Kohler pro I have saw was a command. Single or twin. There's should be a model number in the shroud just like normal. That'll tell ya, you just may have to do some parts looking to see what the part numbers come back to then compare to what goes in a command
Simple Green softens tires...It may be the wrong time of year as Al mentioned, but an old truck puller trick is to leave them mounted and set them on the shed roof in the fall. The sun and elements over the winter will harden them up for spring when pulling season starts. That's about the only way to do it without an oven that I know of personally.
Personally I would use 3/4 .058 wall moly, that's just me. And speedway motors sells some really nice u joints made by sweet racing that have needle bearings in them instead of a solid bushed type u joint. ALOT better in the end and they last a lot longer
I built all mine out of aluminum. With all the weld in bungs and fill cap from the chassis shop I had around $75 in parts. If ya can't TIG aluminum then you'll have to find someone to do that part too. I usually made mine so they held a gallon. On a 30 lap race with some of the cautions that always seem to happen I would use up to 3 quarts.