318 build up

looking for a street machine, the 12 or 11 sec. was a notion i got from my mopar buddy , he has like 13 cars, told me to build up the 318 for street, then plumb it for a 50 to 100 n.o.s. shot for the track times, he said the 318's he used to run could handle small n.o.s. shots all day long at the track , and just run pure engine on the street, i want to keep it realistic, as i said, not afraid of testing the 904's capabilities, is there any way of beefing up an 8 1/4 rear, or are they fairly sturdy ? i just want a fun car that does have some bite behind its bark, i already enjoy the heck out of driving it now w/ a tired stock 2bbl. 318, thanks for all the help here , especially for a reformed ford addict !!!