[dataway]

So my GTO was came originally with a clock .... I'm trying to decide whether to keep it original with a clock, or install a repop tach. (I'd have to use a repop clock too).

This is not a concours or even absolutely correct restoration, but it's very close to one as far as being true to the PHS and OEM parts used. So far I have avoided any option or change that was not original (except 71 NOS Qjet). But a tach would be cool.

Now these repop tachs don't work with aftermarket electronic ignitions (I'm using points currently) so down the road if I modify the ignition it might not work. Also ... I can add a period tach of some sort if I want to, as I will probably be running an auxiliary gauge set anyway (idiot lights only originally).

Whereas a clock would be as ordered, would continue to work, and would remind me more of what the car was like 45 years ago when I bought it.

What do you think?

[Formulajones]

Every repop tach I've bought work fine both with points and electronic ignitions.

Dad is running an MSD setup on his GTO and the factory tach works fine. It's a repop I put on a couple years ago.

Same deal on my Chevelle, Camaro, Firebird etc...

[Scott Thelander]

from my purchases repops dont illuminate very brite ...

nos clock on e pay right now ....

Scott

[Formulajones]

Yep, I swap them all over to LED's.

[Half-Inch Stud]

My 68 In-Dash Tach got a new lease on PERFORMANCE by grafting a Bosh movement ( from ADv auto). Took meticulous care to modify the nonstock stuff to fit within the stock tuff.

Was not easy, but is done.

[dataway]

Jeez all the in dash repop ads I see say they don't work with electronic ignitions. But you are not the first to tell me they do.

I didn't mention what year .. but I've got a 68, that NOS clock is for 67 and earlier I think.

The sylvania LED bulbs I put in the instruments seem to work great on the bench as far as brightness, will go the same route with the tach or clock.

Hmmm, you've got me thinking for sure ... a tach would be way more useful than a clock. And I don't plan on selling or showing the car so really doesn't matter what goes in that hole I guess.

[Formulajones]

I guess it could make a difference depending on what wave signal they use or what ever they call it.

I can tell you some things for sure based off my own cars.

Our Camaro Z/28 tach had been removed and was MIA, so I bought a repo tach to replace it. At first the tach was used off the points. I later installed an MSD box, which sends it's own tach signal. So I moved the wire to the box, and it works just like it always did.

I converted my Chevelle to a factory tach just this year. It already had an MSD ignition system that I've had in place for the last 25 years. The factory tach wired to the box for signal, just like the Camaro. It works perfectly. When I installed the Sniper EFI it gets it's same tach signal from the box too, (same terminal) and both the Sniper and factory tach read identical. He also has a factory (not reproduction) in dash tach for his GTO. I'd bet money it would also work off the box.

My Firebird still has points triggering it's factory tach, it's not a reproduction tach but I suspect it would also work if I were ever inclined to put a box in that car too.

Dad's GTO uses a factory hood tach that I installed a couple years ago. He already had an MSD system on his car for about the length of time I've had it on the Chevelle. I simply wired the hood tach right to the MSD box, works perfectly. Also have his Sniper EFI tach signal coming from the box, and they both read identical.

So as far as aftermarket ignition is concerned and working factory tachs, I only have experience with the MSD stuff, and it's all worked fine. I would assume the MSD boxes put out the same wave signal that all tachs are looking for.

I can't speak for some of the other aftermarket ignitions out there.

[dataway]

I see the Ames catalog shows some of it's hood tachs that do work with an MSD, some that don't. Doesn't show any in dash tachs that work with MSD.

I guess it's the signal voltage that some of the repops don't like. OEM was around 12v, they say MSD is 18v.

[Scott Thelander]

https://www.ebay.com/itm/17449940056...cAAOSwxvNfnEkZ

[Formulajones]

Originally Posted by dataway

I see the Ames catalog shows some of it's hood tachs that do work with an MSD, some that don't. Doesn't show any in dash tachs that work with MSD.

I guess it's the signal voltage that some of the repops don't like. OEM was around 12v, they say MSD is 18v.

I don't see why the hood tachs would be any different than in dash tachs, they all serve the same function. Honestly I never paid any attention to the literature, I just buy the tachs and hook them up, with either points or MSD, and they always work.

Technically speaking, the inner workings of the in dash tachs I've bought for the Chevrolets here really shouldn't be any different than the Pontiac in dash tachs. It's just a tachometer. I really doubt there are more than a couple manufactures making these things.

[android 211]

My quartz clock conversion actually runs my battery down in a week of not driving unless I keep the battery tender connected.
If you routinely run it up to the redline - hood tach and if you don't want that then in dash tach next best thing.

[dataway]

Scott, thanks, that's a pretty good deal considering it comes with the lights. New lens is only $24. Is the "Rally" clock the same as the standard clock? That one didn't show up in my search.

Decisions, decisions, I've got another few weeks before the instruments go in.

Update: Just made an offer for a nice, working used clock on ebay, might get it for $80 and still has the OEM light sockets.
I'm not going to be running this thing to redline ... probably ever. Just wanted a tach to watch idle speed, shift points etc. Maybe I'll rig up a period aftermarket tach and use a magnet mount under the dash above the console ... where it's just about useless as a redline tach

[A Schab]

I’ve had problems with oe tach’s When used with Pertronics.

[Carousel72TRed]

Originally Posted by Formulajones

I don't see why the hood tachs would be any different than in dash tachs, they all serve the same function. Honestly I never paid any attention to the literature, I just buy the tachs and hook them up, with either points or MSD, and they always work.

Technically speaking, the inner workings of the in dash tachs I've bought for the Chevrolets here really shouldn't be any different than the Pontiac in dash tachs. It's just a tachometer. I really doubt there are more than a couple manufactures making these things.

Hi Formula Jones & Dataway,
I have read the same thing in the Ames catalog on their reproduction tachs that they only work with a stock points distributor or Delco HEI distributor. Dataway please let me know if you get an in dash tach and if it does work with the ignition you have. I have a Summit HEI distributor and it looks just like a Delco HEI distributor. I would hate to purchase the in dash tach from Ames or OPGI and find out it won't work in my car.

[OCMDGTO]

I've always had an in dash tach, both original and aftermarket from Ames. No issues at all working with HEI. Only complaint I have is brightness.

[north]

all A body tachs in 69 were considered rally clocks. As for hood tach versus dash tach here are my thoughts...

hood tachs (original or repop all end up fogged up or seized up in short order. Dash tachs that work when you put them in generally work forever, it's just a reality of a hood tach getting wet, roasted by sun and engine heat and slammed etc

That being said, a hood tach is a nifty looking gadget and I like the vibe they give the type of car that looks appropriate with a hood tach.

Either way I don't think adding either one does any harm in value to the car even if it is a high buck car as long as it is done correct (repro dash tachs don't look quite right to me).

[padgett]

Dash and Hood tachs mostly use the same circuit (can take the transistor circuit from a 72 dash tach and put in a hood tach.

Most issues were solved by the vent hose that pulled moisture out of the hood tach. Mine works just fine.

[Greg Reid]

My car had an older repop dash tach when I got it. The car had also had been converted to HEI. It worked fine for years but suddenly stopped. I never got around to troubleshooting it but guessed at the time that it was what I had heard about HEI and older tachs being incompatible.
Now I'm thinking maybe not.