Is there anyway to figure out what length to make the driveshaft without having the rearend. It's a 400 transmission and a dana 60 rear end. I'm running out of time and if I wait on the rearend and then have the ds custom made I don't think I will have enough time.It's the strange dana 60 with my mounts and brackets on it. Has anyone ever used a dana 60 with a 400??? I need to know the sd length ASAP????