I was searching the threads on the site and i found no problem that exactly explained mine so i will just ask and see how far i can get with it. I have a 96 camaro just dropped a 383 stroker in it walboro 255lph, new oil pump, new disti cap. and just the little odds and ends. I was driving it the other day on a 90 degree day really humid though and the car starts to studder after about 20 mins worth of driving i cotinued to drive it but it just finally stalled. I turned it back on and i heard the fuel pump kick on and it graddually revved to a high pitch humm and just kicked off and wouldnt come back on. but then the next day i took it out in a cool morning and it worked like a dream nothing was wrong but then again it got hot outside and it did the same thing to me. I am in complete dissaray at what this might be i changed the fuel filter alll fluids look good so cld this be a fuel pressure regulator or is it the damn fuel pump or cld an 02 sensor cause this because the only code is the hearter circuit malfunction on sensor 1 bank 2. Help me please and thankyou.

 

do a fuel pressure test on it first. when it dies check for spark at the plugs and see if u can narrow it down to one, fuel or spark. could be fuel pump, fuel pressure regulator, coil, ignition modual.

 

Did you do anything to upgrade the fuel supply into the engine? The 383 is a bigger engine, about 10% bigger than what you had. And a bigger engine needs bigger fuel. I wonder if you might be having a lean fuel mix problem, from the 350 injectors possibly being too small?
The engine naturally runs richer when it's cold, in "open loop" mode, and leaner when it's hot. Your fuel management system may be supplying just enough fuel to keep the engine happy, until it heats up and goes into "closed loop" mode.