Back from the machine shop with the countersinking finished and trial fit,Now I have 3/8 (.375) side clearance form sprocket to swing arm plus 1/2 the sprocket is .150 so this gives me .525 for 1/2 the chain, which is about 1.000 wide total, Measured the length for the axel spacers on each side, now to re-do the mounting bracket since the upper frame rail is going to be wider so that's next with the upper rails themselves widened, then to the jack shaft, more measurements tomorrow (Sunday) then off to my steel supplier for swing arm brackets 3/8 this time? and some tubing for the swing arm push rod and to figure the bell crank,