350 to 454 wiring

[87chevyon42s]

I have a 1987 chevy 1ton 4x4 it had the tbi 350 in it. I now have put a tbi 454 out of a 1990 gmc in it. I just need to know what kind of wiring needs to be done to it. I have all of the wiring that came out of the gmc and the computer. I dont have the wiring from the chevy.

 

[Thunder]

350 and 454 TbI wireing is pretty much the same . Almost plug and play. They use the same ECM just have to pull out the 350 chip and plug in the 454 chip. IAC connectors are diferent but you can buy a adapter. Or Solder on the 454 connector to the 350 harness. Also the TPS may be diferent depending on the year.

 

[4X4HIGH]

You may need this, http://www.turbocity.com/product_info.php?cPath=16_23&products_id=50

Also this, http://www.turbocity.com/product_info.php?cPath=16_23&products_id=44

 

[87chevyon42s]

so do i need to have my old wiring from the 350

 

[4X4HIGH]

You need a harness from either vehicle. If you still had the harness from the 87 chevy then all you would need is possibly the 2 adapters harnesses i linked to. If you have the harness from the 454 truck then you have everything you'll need.

 

[87chevyon42s]

i have the harness from the 454 but what about the big plug on the fire wall to the fuse block that plug right there is different.

 

[4X4HIGH]

You need the complete harness then.