Took a few minutes tonight and looked at my factory wiring drawings. Something was nagging me in the back of my mind...

The '74-'75 engines DO NOT have a fuel pump relay... They are fed from Fuse 12 coming directly from terminal 15 of the ignition switch. The safety shut off relay was added in '76

Maybe someone added a relay to your car, or it is for something else.
May I suggest you add one for safety? A Ford Bronco II roll over switch or similar would be what I would use.

For whatever reason the '74 factory workshop drawings are all black and white. while every other year is in color... I am going to do a wire by wire comparison of function and routing with the '75 diagram to see if the wiring is the same and if one could assume the same for the color codes.

EDIT..
If anyone has a color factory current flow drawing for a '74 I would like to borrow it to copy on our color print machine and return it to you.

Dennis,
Its a long way for me to post the original to you but if this is what you are looking for PM me. I don't suppose you have a chart or can make a harness for a C3?

http://forums.pelicanparts.com/uploa...1391429691.jpg
http://forums.pelicanparts.com/uploa...1391429729.jpg
http://forums.pelicanparts.com/uploa...1391429774.jpg
http://forums.pelicanparts.com/uploa...1391429815.jpg
http://forums.pelicanparts.com/uploa...1391429852.jpg
http://forums.pelicanparts.com/uploa...1391429891.jpg
http://forums.pelicanparts.com/uploa...1391429926.jpg

Cheers
Bill

I figured out the wiring. Dennis was right, a PO wired one of the relays in the engine panel to power the fuel pump. Once I got all the tape removed I was able to ring all the wires and move several positions in the engine harness plug to match the chassis harness. I also added the air filters:

http://img.photobucket.com/albums/v6...psr1nodw7j.jpg

http://img.photobucket.com/albums/v6...psvuoruxlo.jpg

I little more wiring work and some mods to the engine electrical panel to mount the MSDs and this bad boy gets installed!

Are those blaster coils? Where are the boxes going?

Todd

Nice job detecting the custom wiring gremlins. :)
Your engine looks great.
And a special thank you to Bill for scanning and sending me a copy of colour diagrams. :)

They are blaster coils and the boxes are going where the old box, accumulator, and fuel filter used to go. Pictures this weekend.

Looks great. Bring it out to the HCR. You can finish by March right?

I'm already signed up and plan on being there. I should be on the road by the end of the month.

Great. We are all looking forward to the event. It will be nice to meet you.

You too, Jamie. See you there!

Congratulations on the build! As others here, I am looking forward to "final" pics!
Good luck with everything.

Thats a work of art!

Got a lot done today!

This would have been entertaining to watch. I had to remove the stock exhaust while the engine was dangling from the hoist. What a pain!!!

http://img.photobucket.com/albums/v6...pspx1qvsw6.jpg

Everything else went pretty well. I grit blasted all the tin and got it painted. Going back on tomorrow. Installed the flywheel, clutch, and tranny. Tried to bolt on the starter, but the studs are too long for the barrel nuts. Off to the store tomorrow. It's really starting to look good!

http://img.photobucket.com/albums/v6...psk8hocuvi.jpg

http://img.photobucket.com/albums/v6...ps3xeevvre.jpg

http://img.photobucket.com/albums/v6...psdbolte6r.jpg

http://img.photobucket.com/albums/v6...pshujrfdev.jpg

Engine is going in next weekend! I ground out the old sway bar brackets and welded in the new ones, cleaned and painted the spring plates, installed he Rebel Racing bushings and coilovers, and finished the engine wiring and MSD harness. All in all, a productive weekend!

http://img.photobucket.com/albums/v6...psscsrzpar.jpg

http://img.photobucket.com/albums/v6...psawrbcd8g.jpg

http://img.photobucket.com/albums/v6...psgrm6jdzg.jpg

Once the engine is in, I still have to install the front oil cooler, but at least I move to the front.

MSD boxes installed and wired:

http://img.photobucket.com/albums/v6...psqnlrdarg.jpg

I'm now going to attempt to pull the mechanical speedo cable with the wires for the electronic version attached for one easy remove/install. Fingers crossed!

In your picture of the MSD boxes, what is the silver annular ring on the outer half-shaft end, between the bolt heads and the boot retainer?

Good question?

And then...

...it's in!

http://img.photobucket.com/albums/v6...ps79tnl0oe.jpg

http://img.photobucket.com/albums/v6...psoww4mqx4.jpg

http://img.photobucket.com/albums/v6...psi3lxwkqj.jpg

http://img.photobucket.com/albums/v6...psnrwz5f7c.jpg

Next up:

- connect everything
- reinstall rear bumper
- move to the front and install front oil cooler

Great "marriage"!

sweet! after it's dialed in, don't forget to post some vid clips!