save the work of fitting a new rear, and just get the 3.38 gear set for the original rear, also, what's the point of an OD T5 with the 3.38 or even 3.42 gears? my 283 pullin a stock 3spd and 3.9 gearset has immense pulling power, more acceleration than a sane person needs, and will cruise at 60-65 easy - w/ the 3.38 gears my mileage will increase, highway speed jump prolly 10mph at least w/ lower RPM, and everything else will still be great!!
course, others might need somethin to fill the time and use up all that xcess cash on hand
Bill