This is going into a 93 GMC P3500 Forward chassis bus, about 8 Tons. You can imagine that 6.2 was a bit light for this frame, though it did get us cross country and back safely. I pulled a 99.5/4R100 out of an E450 for the swap as I needed the parking brake on the trans.

I am about 70% through this one and what a road it has been, This is new territory for me so it has been a lot of learning. What a size/weight difference between these blocks.

I had to build my first engine cross member for this one to work right. I tired modifying factory cross members and could not get it to sit right. I am not a welder or fabricator, just in hobby. I have a Miller 140 to get small projects done with. I used 1/4" 2x4 and some 1/8" sheet for the two bottom joints.

I thought I would share what I came up with as a first timer. I only tacked it together to get it to a real welding shop. I am leaving it up to the welder to make sure it is strong enough for this beast.

 

Not a bad start

I'll caution you about working room around the 7.3 PSD. I had one in an E-series van and it was miserable to work on because its shoe-horned in there, and the massive dash/cowl is in the way of everything to do with the fuel system. Makes you want to take the engine out in order to do any significant work.

Hopefully your P-chassis works out better.