1998 4.3 to 5.7 swap

[Hazmat Truck]

Electrical wise are the ecm and wiring harness for engines the same ? I saw somewhere that the 4.3 and 5.7 share the same. True ?

 

[slow_c1500]

If we are talking about vortec trucks, then no. The injector connectors will be different because the 5.7 has 8 and the 4.3 had 6.
Not sure about tbi.

 

[L31MaxExpress]

If we are talking about vortec trucks, then no. The injector connectors will be different because the 5.7 has 8 and the 4.3 had 6.
Not sure about tbi.

The V8 connector is easy to swap and only requires 2 new wires run to the PCM.

Swapping 4.3L v6 to 5.0L or 5.7L v8