I have an 87 Z28. First I will give you the vehicle specs, then I will describe the problem.

305 TPI
SLP Cam ( Duration 206/212 Valve lift .480/.487)
Accell 30# injectors
MSD 6BTM ignition
Paxton supercharger 8 PSI
3.73 rear gears
Flowmaster cat back exhaust
Stock exhaust manifolds
Year One PROM calibrated to above specs

Now the problem:
The car runs fine hot and cold, until I run it at full throttle. Under WOT black smoke comes out the exhaust( running rich) but the car responds well. After this the engine begins to miss and stalls out at idle. It is hard to restart and will not idle. After the engine cools down, it runs fine again. I know the injectors are large for a 305, but I contacted Paxton and Summit prior to purchasing them and both felt they would work with the proper PROM. The timing is set at 6 DBTC and fuel pressure is at 45 PSI. Compression is between 90-110 on all cylinders. If anyone has any ideas, I would like to hear them. Thanks.

 

It was the O2 sensor. Car runs fine now.