454 to 350

[sledheadak]

i have a really nice clean 89 1 ton new body style with a bad 454 in it,i have a nice running 350 sitting here,what mods would need to be done to put the 350 in place of the 454 other than exhaust etc.mostly wondering about the wiring.thanks

 

[Thunder]

If its a TBI 350 almost all the TBI connections will work except the TPS sensor. You can get an adapter for that. The ECM is the same but you will need to pull the 454 chip and swap the chip from the 350 ECM.
Most all your other wireing should connect up without problems.
TBI 454 and 350 used the same wireing harness.

 

[4X4HIGH]

Wiring wise the TPS might have a different connector and the IAC motor does have a different connector (don't try using the 454 TBI unit on the 350, it won't work). I know that Turbo City offers a harness adapter to go from 350-454 but not sure going from 454-350. You could easily splice the wiring though if you're not afraid of doing so. Make sure you install a chip for a 350 and also use the proper knock sensor.

 

[dave w]

I am wondering about the intake manifold on the 350. If your 350 has a Quadrajet intake manifold, you have the option of using the 454 TBI / Quadrajet adapter with 350 injectors and a 350 PROM. With the 454 TBI on the 350 ... NONE of the wires need to be changed. Some of the local parts stores near me sell rebuilt 350 injectors for about $38.00 each.

dave w

 

[4X4HIGH]

I am wondering about the intake manifold on the 350. If your 350 has a Quadrajet intake manifold, you have the option of using the 454 TBI / Quadrajet adapter with 350 injectors and a 350 PROM. With the 454 TBI on the 350 ... NONE of the wires need to be changed. Some of the local parts stores near me sell rebuilt 350 injectors for about $38.00 each.

dave w

ALL 454 IAC motors use a flat 4 pin connector while 350's used a square 4 pin connector. Also ALL 454's use a bolt on IAC motor and the 350's are screw-in style.

 

[uglyangelracing]

I have a 305 tbi on a stand in the shop if you need anything