Getting a new driveshaft made tomorrow (locally). They can do 3 or 3.5" diameter (steel). Both u-joints are 1350.

Running a 3" now.

Any reason to go to a 3.5? 640 HP or so + Spray on too small a tire but might change some day.

The only reason NOT to go 3.5 is clearance, but I think that will be fine.

What size is a Denny's nitrous ready?

i have a 3.5 in my 71 and it fits fine the only prob you might have is if you got a driveshaft loop or not ,if you do you might have to modify it a little .mine would slightly rub with suspension down so i unbolted it and cut off about 3/4 in.

I have a custom 3" with 1310 ujoints in the nova now. Hasn't broken yet....but it makes me nervous.
Good to know that can do 1350 joints on a 3" shaft. I don't have room for a 3.5" shaft. (X-pipe is too close)
What do the folks building it recommend?
Ron

They don't recommend anything, they build to spec, which is fine with me. They built my current one and it is very nice. My driveshaft hoop is what is close as well, but I can modify it.

The current one is a 1350 on the front and 1310 on the rear and it has been fine.

I would stay with 3 inch, since you can get it made with the 1350 joints. Am assuming that the wall thickness is the same on both the 3.0" and 3.5"?? If both sizes of tubing have the same wall thickness, there really isn't any advantage to be gained in the larger diameter. The large diameter driveshaft will weigh a tiny bit more and the weight will be further away from the axial centerline of the shaft, which serves no purpose whatsoever.

i have a nitrous ready from Dennys...its 3.5 inches and a very nice product....fit great in my 66 even w/ 3in exhaust w/ crossover...its only 1/4 inch wider on each side...team chevelle members get a discount as well .. SEAN