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MG MGB Technical - Changing Dash Panels

I have the entire Dash (including switches and gauges) from a '74 B. I also have the entire wiring harness from the same car. I want to install it in a '77 B. Aside from the difference in heater controls and cables, and the speedo cable, is anyone aware of anything that would prevent such a "swap"?
JR Ross

Prevent? Nothing is impossible given enough time, money and ingenuity.

Mounting points varied from time to time between eras and markets. Also temp senders and gauges. Earlier heater fan is single-speed whereas later switch is two-speed, but that just gives you two Off positions :o) 74 is chrome bumper (assuming it is not 74 1/2) whereas 77 is rubber so differences in ignition and many other electrical circuits, particularly for North America.
Paul Hunt

Hi do not know if this is a problem with the 77 B but I have a 68 B and 74 1/2. They have a different diameter speedo and tacho. Also the speedo has different gearing as the speedo drive in the gearbox is different. Regards Ken
K Stuckey

Hey Guys,

Thanks for the input. I guess I wasn't clear enough. I have the ENTIRE Dash and Wiring Harness, so all of the gauges, switches, and connectors are available. I even have the speedo cable from the '74.

My question should have been: are there any PHYSICAL preventatives, such as mounting points, curvature of the Dashboard, etc.?
JR Ross

"I have the ENTIRE Dash and Wiring Harness, so all of the gauges, switches, and connectors are available"

That may well preclude a problem with instrument sizes but that's all, and unless you have the rubber bumper 74 then the speedo gearing is different as Ken says, by about 25%.

All your 77 instruments and controls have to interface with 74 components, and the dash harness has to interface to the main harness. If you change the main harness as well that has to interface to all the components. There are many detail differences.

Physical mounting is but just one aspect, unless it is not intended to run afterwards.
Paul Hunt

Hey Paul,

Thanks for the info.
I guess I really "screwed up" in the asking of the question.

I find myself guilty of what I've seen a lot of others posters here do. I didn't give enough detail info.

The '77 car has already been "converted to a C/B model. The driveline is from a '73 B, so speedo gearing is not a question. since I am replacing the ENTIRE Dashboard, with the instruments and switches, matching the wiring behind the dash, shouldn't be too much of an issue. The "under hood" wiring should not be too difficult, although some "modification and adaptations" may be in order, since the smog controls are gone and the Anti run-on system is gone as is the Service Interval Counter.

Thanks again
JR Ross

This thread was discussed between 28/05/2013 and 30/05/2013

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