5.7l injectors in a 7.4l TBI

[eyeroc87]

The 7.4 TBI is off a ‘89 3500.. I have my manifold bored to accept 2” bore. I have a set of 5.7 injectors, I have replaced stock fuel pump with high pressure pump. So maybe police injectors or 7.4. Just thought 7.4 were to much. It’s going in a ‘94 C1500.

 

[Stokes1114]

I would use the 5.7 (61pph) injectors and adjust the fuel pressure and the injector flow etc within the chip. If your not programming your own chips now is the time to learn. That combo is going to need it to run well.

Edit..I have found that trying to use the 7.4 (80pph) injectors that the motor will like them up higher in the rpms, but at low rpms and idle you will have a very hard time keeping it from being too rich. Upping the pressure on the 61pph or 65pph is a much better starting point that will make tuning it easier.