ok so im looking at getting a 41 jeep flat fender p/u. i want to do a diesel swap but dont know what do put in it, im looking at the cummins 12v and the 4bt. im not sure if the 12v will fit and am worried about weight. i want to make it a best of both worlds type rig, fast and responsive for playing in the sand dunes and mud, but torqy and low geared for rock crowling. i want a mechanical engen. i included some pics on this post http://www.dieseltruckresource.com/dev/showthread.php?p=2084530&posted=1#post2084530 . what do you think, thats a 350 in it right now.

A 6BT is over 1100 lbs, a 4BT is over 700 lbs, a 350 SB is under 600 lbs.

Consider a Cummins 3.3 which is about the same wieght as a SB
http://www.dieseltruckresource.com/dev/showthread.php?t=112807

ya but 215 ft lbs, copaired to over 400 then to over 1000 if i want it from the 12v