Factory tachometers???
 

So I bought a box full of old tachometers. One of the tachs has 1957 GMC in sharpie. I’m trying to find out any info on these tachs and not having a lot of luck so I figured I would ask here. The longer body is throwing me off and also note the 3 prong electrical plug

Did the 55-59 trucks come with factory tachs? If so are these the correct factory tachometers? (Aside from the Stewart Warner)

Can anyone give me any kind of info on these?

Re: Factory tachometers???
 

I'm thinking the 4000 rpm says that it came out of a Big truck with a 6 cylinder diesel in it.

Re: Factory tachometers???
 

good call mr48, can't say i've ever seen a tach in a pre-60s truck

Re: Factory tachometers???
 

I found this page online showing the available tachometers for 1956 GMC's. I had a 8000 rpm factory tach cluster once and my understanding is the 4000 rpm tachs were for 6 cylinders and the 8000 rpm were for 8 cylinders.

Re: Factory tachometers???
 

You learn something new every day in this group. I'd bet a reare item in half ton though.

Re: Factory tachometers???
 

They were a bit pricey back in '56 at $42.95

Re: Factory tachometers???
 

Thank you for finding that. I could not come up with reference material. I actually planned to dig out my GMC owner's manual this weekend.

Re: Factory tachometers???
 

The Suburban Carrier was GMC's version of the Cameo. Those trucks were often sold with all the options. Deluxe cabs, tinted glass, two-tone interior, arm rests, etc. But most of them that I've seen had clocks rather than a tach. Possibly because most of them that I've seen had Hydramatic transmissions.

Where I've seen tachs it's always been in larger vehicles. Construction trucks, buses, anything with a manual that carried a large load. I suppose the boss would be pretty angry if someone blew an engine...

Re: Factory tachometers???
 

I would expect to see a tach in a 2 ton. I had a 57 GMC 3/4 ton big window rust bucket that had left the factory with every bell and whistle that you could stick on GMC picckup in 1957 and Think it had a clock in it. It had left the factory as a V8 automatic truck. And came with a 283 and power glide when It came to my place. Top speed was about 50 mph as it had a very low geared rear end that someone had stuck in it. It had belonged to my mom's long time companion and had spent years up in the San Juan Islands as far as I can figure. Some guy finally bought it for parts.