There are quite a few folks who have installed a V8. I get the impression that one of the difficulties is that the steering column gets in the way of the exhaust. There should be quite a few posts on the subject.
Also, lots of us have gone to 16x6" wheels on these 8 lug trucks. There are a lot of posts on that too. New trialer OEM style seem to work out OK and now Wheel Vintiques are selling new ones to fit.
