89 350 to 87 454 tbi swap

[Essig3]

Need advice on wiring I have a 89 gmc with a 305 switching to a 454 out of a 87 chevy both have tbi what needs to be done have both computers and tbi and have both wiring harnesses

 

[b454rat]

Both will be 7747 chip, so can just swap that out. And IIRC only difference in wiring is the TPS and IAC...

 

[Essig3]

Both will be 7747 chip, so can just swap that out. And IIRC only difference in wiring is the TPS and IAC...

So can just swap throttle boddy of my 305 or is that to small if small what do I need to do to rewire the TPS and IAC

 

[Drunkcanuk]

I would think the 305 injectors won't be able to keep up with the fuel demands of a 454.

 

[Road Trip]

I would think the 305 injectors won't be able to keep up with the fuel demands of a 454.

DC is right. In another thread we dug up some vintage info on the different injector
capacities: (SBC vs BBC TPI injectors) Looks like you need to move the 454 TBI with
the engine, and then rewire as needed to hook up the TPS & IAC.

 

[Schurkey]

...and get a transmission, front springs, radiator, and rear axle that will withstand the 454.

 

[b454rat]

I did alot of small block to big block swaps n never swapped all that lol. One was a car, Saginaw 4-speed, 7.5 10 bolt with 295/50s. A truck won’t see the difference as much as a car would, but it’s not a ad idea. The 305 TBI won’t work very well. Pretty much need a donor truck or 100% complete motor.