Grigg,
First, I want to say that I in no way think your swap is anything but the coolest, in fact after seeing yours I went on a search for a Detroit (but alas they are hard to find on this coast and terribly expensive). As I said before there is an original GMC running around up here with a Detroit and I drool every time I hear it.
Second, I did not know that the P-30 I-beam was that much bigger, that does make me feel a bit safer about the narrowing. I just know that when a forged part is welded back together it will never be as strong as the original forging as the grain structure is now interrupted instead of continuous. I do have a degree in Metals and Manufacturing with a bit of background in metallurgy so I at least have some Idea of what I'm talking about.
Anyway, this truck isn't going to be used for long haul type stuff and while I wouldn't mind a wee bit more speed on the highway so I'm not a rolling roadblock I by no means need it to be anything more then a slow lane machine. I would probably drop a small or big block in it but it would be near the same amount of work to make them fit (more in the case of the BBC) and I would be lucky to see 10 mpg, I would think. So as long as I am going to be doing some cutting and welding I figured I would squeeze in a diesel.
I think that I will find a way to do a disc brake swap to the front at least (P-30 narrowed or P-30 spindles adapted) but I am going to have to do more research where it comes to the rear end before I make any decisions. I may even try the swap with the stock rear as I can always go back and swap it latter.
One more question for you. on the 4btswap site you mention that you see the 5/10 P-30 chassis regularly. If worse comes to worse and I can't find a front axle out here would you have any interest in possibly supplying one, fully paid for of course?
Thanx again,
Jaysin