Whats up guys, so im working on a 96 3500 that we just installed a new 383 stroker in a vortec block. The truck came in with a hard start/ long start issue. Did the swap, replaced all sensors, new plugs, wires, dist., and everything you should when putting in a new engine. New fuel filter, new ignition module and coil. The truck acts like a bad IAC, but have replaced that twice just to make sure we didnt get a bad new valve. Fuel pressure sits at 55 koeo, 60 cranking, back to 55 koer. To get it to stay running you have to give it gas or else it fires then dies at idle, but if you start it with the pedal and rev it a little, it will drop down to a smooth idle. Drives fine. We’re at a loss here. Any ides are much appreciated.
It is also throwing a p1351 code with high voltage in 1 & 4 circuits. Any input?

 

What's the idle rpm when it does idle?

 

hows the MAF?