Originally Posted by Jeebalow

When it comes to driveshaft it's not about how much power it can hold, it's about what the critical speed or shaft rpm is. You may never have enough torque to twist the stock shaft and destroy it on takeoff, but get up to over 100 or 120 MPH and that same shaft will destroy itself. Once you get to a vehicle speed that makes the shaft get to it's critical speed, it will start looking like a jump rope and then say goodbye to it and maybe your transmission and floor.

I went with a shaft from driveshaft specialist in texas. It's a 2 piece steel shaft with 3.5" OD and 1350 joints. Talk to them and tell them what you have and what you want to do with it. I asked for a shaft that can handle 8000 shaft rpm, even though I will likely never get there, due to my gearing and tire size combo. (4.88 and about 29"). They did the calcs and decided to go 2 pieve steel rather than one piece aluminum due to the length. This is in a 95 extended cab short bed truck.