Im highly betting its your pcm. Mine did the same thing, it was weird as hell. I would sit there and rev the engine and the speedo would go up. LOL.

 

Well I finally had a chance to work on the truck, first off I let the truck run for a little while and I checked the temperature of each header and all seemed the same, so I then took some throttle body clean and cleaned the throttle body and it didnt help, so I took the truck to my buddy that did my EFI live and he put the stock tune back in and I took it for a ride to see if it was the tune and it didnt help at all so he put the tune back in, I then swapped my mass air with my brothers to see if it was the mass air and that didnt help at all so I decided to get some new plugs(NGK TR55) and see if one of Delcos I just put in was faulty and sure enough it fired up and ran mint and it doesnt break up anymore.
So thanks alot for the help everyone, Now its time for the built tranny, stall and cam swap

 

Does your speedo still tach up a bit when revved?

This is usually caused by the RF intereference acting on the speedo/PCM wiring.

peace
Hog