A few more things I've found out.
It's good to know the 270 pan will fit, since I pretty well have to use it. I took a look at the military 302 oil pan and it's about 13" deep. It would be even harder to fit than the Perkins.
Also good to know the later distributor will fit. I probably have a couple around, just haven't compared them with the military yet. The late 6's are so common I've actually bought complete engines just to get the HEI.
The flywheel off my 270 will not fit. It's a 4-bolt mount as opposed to the 6-bolt on the 302. I've heard a flywheel from a later 270 or 302 will fit, though. What years use the 6-bolt mounting?
Starter may not be a big problem. I was amazed how interchangeable Delco starter parts are when I needed a 24 volt starter to replace the pup engine on an old Cat D-6. I took tracings of the ring gear and mounting flange and a few other measurements to my local starter shop and they were able to pull a snout, drive, armature, field coils and body off the shelf and assemble a starter. A lot more expensive than finding one in my junk pile, but not nearly as bad as I had expected, either. So it should be no big deal to assemble a 12 volt starter for a 302 if all else fails.
On some forum, I read that the military engine uses side mounts at the front, and it will be necessary to change them. I don't know if it's true of all of them, but the first one I looked at has a front mount like the 270. I'll have to get better access to measure and see if it's identical, but at least it's the same style. The bosses on the sides near the front are used to mount the generator and air compressor.
