SM 420 and NP205 in a CJ-5

I am going to attempt to put a SM420 mated to a divorced Np205 into a 75 CJ-5. I know that it sounds like a long combo but i have done some figuring and I think it might just work. I made a short little driveshaft that measures 4.5 inches from end to end (which is about the same length as the adapter to mate a 420 to a NP205). I will gain a little in putting in the 420 as the bellhousing is shorter (I don't know how much yet as the adapter housing hasn't got here yet). My driveshaft length now is 19 inches center of cup to center of cup. The T-15 and SM420 are about the same length. I will add about 6 inches with the yokes and little driveshaft but I get to suptract about 2 inches for the shorter bellhousing and input shaft. So I think that will leave me at about 15 inches for my rear driveshaft. Does anyone run one that short? I can put in a shortened cardigan (spelling?) type shaft out of the front of an Bronco if need be. I guess if it comes down to it I can move my rear axle back a bout 3 inches and trim the sides and possibly some of the back of my glass tub out to accomidate the axle being further back.
If anyone has any ideas or insight let me know. I would also like to maybe see some pictures of how you bolted the 420 down. The one i pulled out was sitting on a cradle type crossmember and then bolted from the frame to the bellhousing. I have some ideas on this but it depends on how the adapter Bhousing is made. This tranny also had the old heavy duty drum brake on the back which is gonna save me from having to put a line lock in and run brake lines into the dash (not to mention the brake lever looks really cool).
Thanks for any info

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