30 spline Axeles in a 8 3/4

I am useing moser(spelling) 30 spline axles,742 case,430 gears and spool in my 3500 pound 73 dodge dart. I have only ran a best 60 foot of 1.52-1.54 at 10.68 at 125 in the 1/4. i would like to up grade to a 35 spline spool. But when i break this 8-3/4 again i am going to a dana 60. if it matters my rearend is back braced.