I have built a couple so if you do it and need info just ask. I have found that the best rear is a BANSHEE they hold up great and will go 80/90 mph with out a hum. I also build Street Quads Too that may be better for him.Here are a couple pictures and some of them are on YOUTUBE. First one is a CBR 600 OUAD with TRX front and rear and the funny thing was the rear after i put 10" into it fit like a glove. We had this bike up to 140 then it got hairy the other is a KZ 1000 trike I will have to see if i got more pictures it run Crager mags CHEV. The nice think with the BANSHEE rear is you cut it short and use CHEV hubs and weld them up and you got a strong short rear and it stops with the banshee brakes . I have done about three frames that way and one is a sand dragster and all hold up. Both are running around STATEN ISLAND NY GOOD LUCK WITH THE BUILD