I finally got my MPFI L31 intake swap running after a hell of a time and even now I'm having problems. If I let it cool down it starts up almost instantly and runs fine, I drive it around and it drives good then I come home and park it and it wont start back up till it cools off again. I have tried adjusting startup spark at the temps it does it at, as well as crank BPW, I have been trying all afternoon adjusting both of those in both directions. I have even tried more crank BPW when warmer than cooler, opposite of what you expect.

Is it possible for the timing to be right but the disty still be off, like throwing the DRP out of wack or something?

 

i would suggest replacing your coolent temp sensor...its possible its reading a hotter temp than normal after your done driving it...

 

Is your MAT sensor the cage type or the metal cap water temp type? if the latter I have read a lot about them having heat soak issues,meaning that with a hot engine not running they element will warm up to the temp of the surrounding material the sensor is screwed into. The cage type is much better isolated.
Also the Vortec spider injector setup is notorious for leaks. The hoses can leak, and frequently the regulator leaks, which will flood the intake. The injector nozzles also have several issues, they are prone to clogging as well as leaking. The injector nozzles also have a minimum pressure they will operate at, This allows them to maintain a constant head of pressure in the hose so the nozzle will fire as soon as the injector opens. This can be a problem if your fuel pump has any issues, much more so than conventional injectors. I believe this is a 4 bar system, since my 99 suburban runs about 58-60 psi max(tested).
Obviously there are dozens of reasons you may be having hot restart probs, but the above are some of the things that potentially related to your manifold/injector setup which is different than the traditional systems most commonly discussed on this board .