wwerner

I am swapping my 302 with harness and ecu from a 93 f150 into my 92 300 truck i have both trucks sitting there my question is will I have to change my under the dash harness aswell or will it plug in just like the old one .... please help this project is more overwhelming than I thought...

Chris_1

iTrader: (1)

Theoretically, what's under the dash should be about the same. But you are also going '92 to '93. Best thing is to print out wiring diagrams for both trucks and do a side by side comparison paying attention to colour codes. You can also check the wire locations on the inside plugs against the outside plugs. Mostly they kept the same wire colour to do the same thing over the years. Or maybe someone else will chime in here who's already done that particular swap.
One important detail is that the fuel pressure for a '93 4.9 is 50 to 60 lbs and a v-8 is only 35 to 45 - so I'm thinking you will need to swap the fuel pumps as well or you'll have too much pressure for the 302.
4.9's didn't drop to 35-45 lbs till '95

sylver91

The regulator on the fuel rail adjusts the fuel pressure, not the pump.

wwerner

I have the wiring for the 5.0 and ecu all from the firewall forward all I need to know is ... the big plug beside the ecu on the firewall is the wring the same from 92-93 or should i swap the whole under the dash harness aswell seeing as I have the whole truck just sitting there thanks