We had one at the shop a few years back that a customer had bought, and installed himself- this guy is an engineer at TIMCO aeroautics in Greensboro- a smart guy, heck of a fabricator, and a pretty good mechanic..( we were doing a front end rebuild, and disc brake swap that he didn't have the time to do, because he had spent so much time with the Keisler issue. The thing was barely drivable, vibrated like a cement mixer, and shifted like a dump truck. He had tried to get tech help from Keisler, had asked for a refund, etc, and got NOWHERE.. he was pretty livid. I drove the car, and felt what I described.. we didn't have anything to do with the Keisler situation, but I heard plenty about it. He ended up going auto with a gear vendors, which we did install, and NO PROBLEMS at all- works like gravy. I remember him being ready to choke Sharif Keisler or whatever his name is, because of the holier than thou attitude he was getting from him, telling hil he didn't know what he was doing, etc. I do know that there was no way to get the pinion angle right with that thing, aside from destroying the trans tunnel completely, it was nowhere near a drop in application.. this was on a 70 Road Runner, factory 4 spd car. The trans ended up in a 69 Coronet around here, he never got it to fit right either, and then 2/3 gear went out of it.. it ended up in a junk pile somewhere...