The Stovebolt Site Forums The Parking Lot Big Bolts Loss of Power

This is a strange one, hoping someone knows a secret.
I recently removed my battery holder from the engine bay and fabricated an extruded aluminum battery box, which I mounted under the passenger floorboard area. Ran new battery cables, terminal blocks, kill switch, etc. Essentially, all battery cables new (battery +/- to terminal blocks, jump to kill switch, to starter, to engine ground, and to a ground lug I installed in the engine compartment. All 6ga, all new terminals, all quality parts.

During this process, I also decided I'm going to fix my headlights (replace w/ vintage-looking LEDs), replace my bed & rear lamps, and repair my turn signals. My lights rarely worked right, I kept blowing high beams, and I didn't want to purchase new stuff w/o new wiring.
So, I removed all under-dash & in-cab OEM wiring, plus the engine bay harnesses (it had all been hacked & spliced too many times, w/ varying wire gauges and colors, to make sense of anything without continuity testing each end point).
Tracing wires through a spaghetti mess was driving me nuts.
I have not installed my new fuse box yet. Outside of the battery cables, I think I only have three wires hooked up in the entire truck - one from ignition switch to the starter solenoid, one to the coil from the starter, and one from the voltage regulator to the ignition switch.

My freeway speed was reduced from ~60 MPH to a top speed of 47 MPH.
Could this be due to one of the mystery resistor wires? Any other guesses?

Hy Fosterelli, I am going to assume we are talking about the 1961 C60 in your signature line. Could it be that your differential is in low range? You said you only have three wires hooked up in addition to your battery cables?

It's also possible that some of your wiring work has gotten the speedometer ratio shifter out of phase with the rear end. When the rear axle shifts ranges, there's also a shift made at the speedo drive cable. I'd suggest using some kind of GPS unit to confirm that the speedo indication is accurate, although the engine RPM at highway speed should give you a clue. Is the governor still working?
Jerry

Hotrod Lincoln asked about the governor, I was thinking that is a possibility unrelated to the electrical work. If the original governor is still being used, and the speedo and 2 speed are found to be working correctly, it could easily be a problem with the governor. Adjustments, cleaning and lubrication, and possibly the need for a new governor spring. Years ago while I was working for the local Budweiser distributor, I had a city route tractor that would lose throttle accuracy. We were using 366 and 427 gas motors at that time, Holley 4 bbl with governors. A small spring inside the carb mounted section actually pulls the throttle open when the governor allows it, I found that spring would lose it's tension when the engine was worked all day and good and warm. New spring from the Chevy dealer put it back in business. My '57 2 ton 283 2 bbl uses the same technology and spring, I had to replace that spring 2 years ago due to losing power.

Thanks everyone. Yes, on my '61 2T.
3B, correct, only three wires. Does my diff require an electrical connection somewhere?
Hotrod Lincoln, sounds like you also have something - because I removed my speedometer cable when I took everything apart and have not reinstalled it yet (I was going to wait until I completed the new wiring). My slow speed was clocked by my wife following me from the shop to the house.
The only thing hooked up to my gauge cluster is my oil pressure sending unit line.
My kids are always playing in the truck, curious if them cycling the diff switch, my electric being 3 wires right now, and no speedo cable are all factors.
I'm going to research the governor too...

Ah, memories,... We took wire cutters to the whole truck tip to tail and started over with new wire and the factory diagrams. Only modification was I dropped the coil resistor on the firewall and swapped in a Bosch coil w an internal resistor.
Never had a governor on my 56, but the PO had a carb from a smaller car that the 270 did *not* like. Idled great, just don't expect to get anywhere fast. Well too fast, it tops out at 60 with a good tail wind.