Like the title says I had a 2000 Chevy Express 2500 I think I had a 5.7 or 5.3 motor and I'm not sure which one. I had a custom built alternator for it , 400 amps, I have the new 2007 Chevy Express 2500 which has the ls 6.ltr and need to put it on that one I'm wondering if it'll interchange

 

Rock Auto shows a 2000 alternator while having a wide interchange it's only 2000-back. The 2000 had a 5.7; 2003-up have the 6.0 or 5.3 (or 4.8). A lot of changes to the engine.

You can try comparing the two, a 1995 van alternator is not supposed to fit a 1991 but the only difference is how the back half of the case is clocked, and I was able to get the plug to go in anyways.

 

I figured probably just have to make a bracket and maybe cut the plug and make a pig tail off the 2000