Anybody done that? I have a broken clock that’s just taking up space. I’d love to be able to keep an eye on manifold vacuum at any given moment. Is there anything wrong with this idea? Getting a vacuum line through the firewall is probably the trickiest part, right? Taking a T off the headlight switch would get me vacuum after the check valve, it’d be better to monitor it upstream of that, no? Suggestions, problems, etc?
The vacuum gauge idea is interesting, but you might find it kind of boring after a while. I have run a vacuum gauge to the inside of the car to try to see what the vacuum was to get a better handle on when the secondaries opened, and other diagnostic stuff. Once I got a feel for what was happening it lost it’s appeal.
The movement in your clock can be replaced with a modern quartz movement, or many times the only thing the original needs is to have the points filed clean and square, with a little bit of lubrication. I use 3 in 1 oil on every bearing area, and then use compressed air to blow out all of the excess oil. I clean the points with brake cleaner, file them square, and the the thing usually runs for several years.
A vacuum gauge is way more interesting to me than a clock, I’m sure. I would also think that keeping an eye on it once a day or week or month or whatever, over time you’d be able to catch performance issues that were creeping up on you, no? Clock just tells the time. I mean, how boring is that?!?
It is a good diagnostic tool, but If you want something to catch performance issues, an Air/Fuel ratio gauge will do a much better job.
WCCC has an 8000 rpm tach to go in place of the clock on a standard dash. That might have to be my xmas present to myself.
I’ve got a NOS 3.5" vacuum gauge (made by Sun) on its way to me. Totally looking forward to getting it in there. Seriously, a clock? Cmon.
Gauge arrived a couple days ago. Fits perfect, though the writing will be a bit off-axis since I’ll position it rotated so 15" is straight up. Just bought some hole-strips too, funny choice, I went with a Meccano part (the predecessor to the Erector set) that has holes on 1/2" centers, since there are three screws to mount it it should be great at holding the round gauge right in place. Fingers crossed and all, but I’m nearly certain it will work.
Mount it straight up and down. It looks like someone did a half-assed job with it mounted that way.
Just my opinion, it’s your car do what you want.
Why 15" straight up? It should be more like 18 or so at idle.
Looks like it fits well in the clock opening. For what its worth 15 straight up looks weird to me. I think the lettering being at an angle takes away from the overall look. Will it light up along with the other gauges? If so what color?
Steven
Look like this one?
http://rccinnovations.com/Tachs.php
I purchased mine from RCCI…need to finish up the install, though.
Two reasons I was thinking 15 up. First, it’s the middle of the range, so the range of movement of the needle would be like it should on any gauge, symmetrical about a line that’s perpendicular to the plumb line. And second, if I put it so the writing is plumb but the range on the gauge isn’t, then I have to file down the port on the gauge and use a 90-degree attachment for the vacuum line, since the port will be too close to the bottom mounting screw on the back.
Probably I’ll end up trying it both ways and see which looks better to me and then go with that.
It’s not a light-up gauge. I’m sure I could throw an LED or two down there that would light it up ok, but it’s probably better if I keep my eyes on the road at night anyway right? I wonder if maybe the map lights would get to it enough that I could see it at night? Again, if I find myself bumming out that I can’t see it at night, some LED’s mounted right where the gauge butts up against the back of the panel would probably do the trick.
And who knows, maybe months down the road I’ll tire of it and replace it with an air/fuel mixture gauge instead. Or a microwave, a really small one just big enough to head up White Castle burgers, do they make those in 12v?
Now a microwave would be the cat’s meow! Way better than a “clock”…heck maybe they make one with a “clock”. LOL!! Burgers and classic cars go hand in hand. 
Steven
A microwave would be perfect behind the roll up door of an STD console.
But that’s where I was planning to install my Mr. Fusion.
That is where the rotisserie goes that runs off the exhaust heat.
It’s not large enough for a chicken though. Cornish game hens maybe?
quayle
Cornish game hens and classic cars go hand in hand! 
I should have known that! Man I’m way out of touch with current trends. 
Steven
Nice fit. Offset mounting looks good too. Just like many of the old race cars that had the tach rotated for max RPM’s at 12:00. While some won’t get it some will. LOL.