Since you have already modernized the transmission and rear end why would you want a 2 piece driveshaft. Tell your driveshaft company the HP rating of your engine and let them build a 1 piece shaft that will last you forever.
My 400+ hp ‘62 C-10 with 700R4 has a nicely made steel shaft that will handle anything my engine can throw at it.
Who did you end up using? My issue is that the shaft needs to be 66.25" long. Most places are capping out at 65" and won't do it.
