bedside problems

ok guys ive got a problem i need an answer to by this sat hopfully. im doin a full frame rebuild from scratch. ive backhalfed the frame with 2x3 box tubing and narrowed it 2 inches on both sides. ive biult the one off control arms up front and shaved the shock towers. then eleminated the c-bars. the problem i need answered for my biuld future wise is when i bodie drop it will the tires get into the bedsides. im running 255/35/20. i thought of narrowing a 02 chevy fullsize rearend but thats a little costly. i was told an isuzu rearend cant be narrowed so im stuck on my biuld right now and need to get it movin so i can biuld the cantelever setup. thought about just sellin the 20s because there 9in wide for a realy narrow 22" any help with figuring out this nightmare would be greatly appretiated

depending on which model truck you have it might be able to be narrowed. what are the first 4 digits of your vin?

has anyone heeard of using a toyota rearend from an 87 forunner. ive heard there about two inches narrower and have the same lug pattern. if this wont work, how wide of wheel and tire and what offset 20s i would need to not get into the bed sides when i do a 3 1/2 inch body drop.