I did some research on this conversionm into my '68 c10. Most of the info here is accurate, but a couple other things to consider.The approximate weight of the 6.2 is same as a big block, and using the big block mounts will work. 6.2's were used in half ton trucks, but only the "C" version of the engine with egr mounted in the intake. "C"=light duty, "J" code= heavy duty. "J"'s were used in 3/4 and one ton applications, make better h.p. and have beefier heads, injectors, and cranks. Find a "J" code for your project if you can. The suggestion of finding a running, complete donor for the hyrdo boost brake system with it's master cylinder, prop valve, radiator, etc, is best. If you find a truck from the '82-'87 vintage, you will be able to use the all the front crossmember goodies you want to swap over.
Getting back to the original question of using original tranny, at the very least you need to swap the torque converter and governor to match the diesel, as it has more torque, and runs at much lower rpm, so the shift points are different. As a personal observation, all of the diesel TC's I've ever seen, from factory, are painted diesel alpine green.
Finally, the 6.2L is 379 c.i.d. The "J" mated to a SM465 in my daily driver for the past five years is still a strong runner at 231K on the clock, and gets 21 mpg all day long, when I'm not towing something. And I just bought a '88 G30 van/schoolbus with a "J" in it for conversion to an RV. I have two "C" code spares on stands in the garage. I'm not an expert, but I love the NA6.2 diesel.
Lots of good info at
www.dieselplace.com/forum/index.php HTH, and good luck with it, let us know how it goes.
