help with61 apache insturment cluster swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

arcticman · 01-19-2021, 01:01 PM

Hello, Im looking information on chaning out my inst. cluster. I purchased a insturment cluster out of a larger truck 1.5 0r 2.0 ton 60-63 it has a tac and actual guages. my original cluster has idoit lights. Im not sure if the cluster im installing had a v8 or I6. My truck has the 235 in it. Ive read that I can install a Tac-adapt to correct the tac if its off has anyone used this product? also will I need to change out all my oil and temp sending units ? Is the wiring somewhat plug and play or will that need changing? Thanks for your help.

**The Rocknrod** · 01-19-2021, 04:09 PM

Temp and oil senders are different. Oil is a tube type from the engine to the gauge. I have no answer to the tach issue.

ray_mcavoy · 01-19-2021, 08:08 PM

I agree with The Rocknrod on the oil gauge ... you'll need to remove the existing oil light switch and replace it with a tube for the mechanical oil gauge.

However, on the temp gauge, it appears as though your existing cluster already has a gauge (instead of hot & cold lights). So as long as the existing temp sending unit is functional, I don't think you'll need to change that.

The 1960 through 1962 factory tachometers used an external transmitter box. And the transmitter box is what's different for 6 vs. 8 cylinder applications. I know the 8cyl applications typically used a Sun EB-9A transmitter, but I'm not sure about 6cyl.

The tach should have 2 terminals on the back marked + and -. Those connect directly to the corresponding + and - terminals on the transmitter box. The "dist" terminal on the transmitter box connects to the negative coil terminal and the "grd" terminal on the box goes to ground. They originally used a 1.35V mercury cell (located inside the transmitter box) for power but those are no longer available. I've heard that a regular 1.5V alkaline AA cell can be used as a substitute but might make the tach read a little higer. And I believe many tachometer repair shops can replace the old guts in the transmitter box to eliminate the need for a battery.

To make the BATT gauge functional, I think you will need to add a couple of wires to the engine & front light / generator harnesses. Unfortunately, the wiring diagrams I have for 60 & 61 don't show the connector pin-outs like they do for the later years so I can't say for sure, but it looks like the cab / dash harness may already have the necessary wires for the BATT gauge present but simply left unused.

01-19-2021, 01:01 PM	#1
arcticman Registered User Join Date: Feb 2018 Location: ANCHORAGE Posts: 137	help with61 apache insturment cluster swap Hello, Im looking information on chaning out my inst. cluster. I purchased a insturment cluster out of a larger truck 1.5 0r 2.0 ton 60-63 it has a tac and actual guages. my original cluster has idoit lights. Im not sure if the cluster im installing had a v8 or I6. My truck has the 235 in it. Ive read that I can install a Tac-adapt to correct the tac if its off has anyone used this product? also will I need to change out all my oil and temp sending units ? Is the wiring somewhat plug and play or will that need changing? Thanks for your help. Attached Images

01-19-2021, 04:09 PM	#2
The Rocknrod Moderator Join Date: Aug 2011 Location: China Spring, TX Posts: 7,280	Re: help with61 apache insturment cluster swap Temp and oil senders are different. Oil is a tube type from the engine to the gauge. I have no answer to the tach issue. __________________ Master Chief, US Navy, Retired 1964 C10 Step-side Short Bed - In Progress 2009 2500HD Duramax LTZ 1948 GMC Panel 1956 Big Window Stepside 1953 5 Window Chevy Stepside 1932 Coupe New Seat Foam for Bench Seats?

01-19-2021, 08:08 PM	#3
ray_mcavoy Registered User Join Date: Nov 2009 Location: Sherman, ME Posts: 2,373	Re: help with61 apache insturment cluster swap I agree with The Rocknrod on the oil gauge ... you'll need to remove the existing oil light switch and replace it with a tube for the mechanical oil gauge. However, on the temp gauge, it appears as though your existing cluster already has a gauge (instead of hot & cold lights). So as long as the existing temp sending unit is functional, I don't think you'll need to change that. The 1960 through 1962 factory tachometers used an external transmitter box. And the transmitter box is what's different for 6 vs. 8 cylinder applications. I know the 8cyl applications typically used a Sun EB-9A transmitter, but I'm not sure about 6cyl. The tach should have 2 terminals on the back marked + and -. Those connect directly to the corresponding + and - terminals on the transmitter box. The "dist" terminal on the transmitter box connects to the negative coil terminal and the "grd" terminal on the box goes to ground. They originally used a 1.35V mercury cell (located inside the transmitter box) for power but those are no longer available. I've heard that a regular 1.5V alkaline AA cell can be used as a substitute but might make the tach read a little higer. And I believe many tachometer repair shops can replace the old guts in the transmitter box to eliminate the need for a battery. To make the BATT gauge functional, I think you will need to add a couple of wires to the engine & front light / generator harnesses. Unfortunately, the wiring diagrams I have for 60 & 61 don't show the connector pin-outs like they do for the later years so I can't say for sure, but it looks like the cab / dash harness may already have the necessary wires for the BATT gauge present but simply left unused.



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