Main power wire into cab

[Kblalock]

Where does main power wire enter cab, on passenger or driver side? Is it black and orange on 84 model?

[Gary Lewis]

There is more than one main power wire.  Assuming you have a gasoline engine (you don't have a signature so we don't know anything about your truck) the best wiring diagrams for your '84 are in the 1985 EVTM: Documentation/Electrical/EVTMs/1985 EVTM.  Then pick Charge & Power Distribution (Gas).

Then, depending on whether you have gauges or idiot lights you'll see there are two main circuits to the fuse box and ignition switch: Ckt 37 is Yellow and Ckt 38 is Bk/O.  I believe both of those pass through the firewall near the fuse box.

[Kblalock]

It is an 84 f150, 4.9 with carb, four speed. Rodents have played havoc with wiring. I went back with a one wire alternator, HEI distributor, and non feed back carb to get around some of the wire issues. I was considering just running new power wire to headlight switch, ignition switch, and fuse box because of the rodent damage.

[Gary Lewis]

Be careful as the power to the fuse box and ignition switch goes through fuselinks - short pieces of smaller wire with a special insulation on it that won't melt.  They serve as the circuit protection to things in the cab and some form of protection is necessary.

If it was mine I'd probably do what I did on Big Blue or others have done - install a relay/fuse box combo on the fender near the starter relay.  Use the fuse slots to replace the fuselinks and the run new wire to the ignition and factory fuse box.

But, since you'd have relay spots I'd then install relays to power the headlights.  Use the existing headlight wire to trigger the relays and you'll have much brighter lights.  And, if you really want to make your HVAC blower work better put in relays to provide the ground and power to it.

Several of us have done all of that and can help you through it.  Oh yes, unless you put in a really heavy wire, like #10 or at least #12 gauge, to the HEI you won't get full power out of it.  So I'd run a relay that provides serious power to the ignition.

[Kblalock]

Have already placed a fuse panel to replace the FLs. I use an HEI on our dragster so am up to par on wiring for it. All the factory a/c stuff has been removed, will prob go back with aftermarket under dash unit. Truck sat in a barn for 13 years but body panels are all in excellent condition and it has very little rust. Going back in with factory rubber floor mat and factory interior.

[Gary Lewis]

Sounds like you know what you are doing.