Drive Shaft Length

Scenario:
I've this '81 CJ-5, currently bearing the 2.5 liter 151 with SR-4 and Dana 300. The plan is to swap in a 360 (rebuild underway) and a T-18, overhauling the 300. Differentials are AMC 20 rear with Dana 30 in the front. The CJ-5 being as beautifully short as it is, I can't help but wonder how long (or short) of shafts to procure. Has anyone made a similar swap and recalls the new shaft lengths or currently runs a similar setup?
I might add that I am currently half way across the planet from my project, unfortunately, so I am unable to put forth any as-of measurements.

 

There are so many variables, your best bet is to just have a rear shaft made once everything is in place. Additionally, if you are adding any sort of lift, you'll most likely need to switch to a CV-style double cardan shaft.

The front shaft will probably have enough play in it to accomodate the swap without modification. And it doesn't need to run as smoothly as the rear since it will generally be intermittent duty and at lower speeds.

tom woods is a great resource. I bought a driveshaft from them in 2006, and just last year they honored the (optional) trail hazard warranty when I needed it modified.
Tom Wood's Custom Drive Shafts - Tom Woods Custom Drive Shafts Custom Driveshafts Specialist

 

That website has quite a bit of helpful information to read as well, much appreciated.

 

I called Tom Woods while laying underneath with a tape measure. 3days later I had a stout driveshaft to put in. Just can't beat that.