Gauge question

[Ceruzziracing]

Okay, so I've been playing around swapping parts among my various projects because I'm too broke to be able to afford new stuff. I really like the size of the gauges on my CB350 twin and have been trying to figure a way to use the tach on my '79 cafe project. I know the calibration will be wrong for the four cylinder so i've disassembled a few of my old gauges in an attempt to transplant the 750 guts into the 350 body. The faces will swap with a little dremel work to slot the screw holes and the sweep will line up properly. Unfortunately, the 750 guts have more depth and I had to open up the back of the gauge body to accept the angled tach drive and framework.
After goofing around for an hour or two, I got to wondering if the 350 four gauges would be a direct swap. So, anybody happen to have a 350 four or done this swap? I know it's a long shot, but hey, you don't know if you don't ask.

FWIW, I also like the 350 gauges because they have the two idiot lights in the gauge face, cleaner look.

[TOOLS1]

My buddy has a set of 350 four gauges, but why do, you think that the twin gauges would not work? Most all the gauges are geared the same. You could test them by chucking the cable into a drill, and running it. If they both read the same, no problem.
TOOLS

[Ceruzziracing]

I believe I read one time on SOHC forum that the ratio is different between the two. Upon disassembly, the two units have several noticeable differences regarding size of internal components. The actual overall mechanism housing is similar in size though. And man, what a simple way to check, didn't even think about doing that with the drill. I have a Christmas party tonight and work a 24 hr shift tomorrow, but I'll check with the drill on Monday and report back.

[Ceruzziracing]

Screw it, the party can wait. Little tach spun at 4800 rpm, big tach 3000 rpm. Oh well, it was a good try.