rich the section width is probably whats getting you.try the 29 x 10 ,not the wide it should work.i have always ran a 28 on my 66 .the 29s are supposed to give a better patch though.my 66 is all steel ,except for the hood and front bumper it has the glass in it.the best thing i ever did was go with a power glide ,the 60fts picked up and the car was much more consitant.i also have had 488s in mine.the 60s was not great but were always in the low 1.50s with the car running between a best 7.12 to 7.20s.on a well preped track a 9 inch will dead hook ,but on a marginal track thats where the wider tread comes into play at our power level anyways.