advanced timing school please

ok ive read the above threads and i have learned quite a bit. i got my timing tape in today, and was wondering... the diameter of the harmonic balancer on the 360 should be 7" correct? i got universal timing tapes from 5.25-8 inches and pretty sure i should be using 7"... just want to be sure.

during my timing light use... my timing light fell and hit the fan and is now broken of course. and i have a bag plug wire.

i had the car running well with no kickback or pinging at 8*advanced. that means i should be looking for a dist. with 26ish initial to get me up around the 34 mark where i should be... and all that with no vac advance ? and then add my vac on top of that to be up around 50something, hopefully.

upon driving the car with this dist... i step on the gas its like the car just has no go to it. it revs without any problem sitting in the driveway, but out on the street it just seems to die out and it has no power at all. am i on the right track with looking into the mechanical advance?