Hood Tach Vent Fitting
 

After Installing a Hood Tach in my 71 GP restomod, I found that the repro hood tach vent kit currently sold is not close enough to the factory pieces to even use for me. I've got NOS Filter for it but the fitting at the heater box in the kit was not an option. So I have designed and 3d printed my own reproduction of the heater box fitting. I've been designing for many years, think its close, had no oem part.
Had them service bureau SLS printed in a high performance thermoplastic. Can anyone give a review based on an actual part they may have? I can make these available if anyone else needs any. Overall length approx 1.25 inches, has the hole for the rivet etc. I'm also going to make my own reproduction filters just for fun.

Looks correct to me.I had been thinking of doing the same. Would be interested in two of the fittings.

I'd be interested in a couple fittings and filters...

Glad you guys can use a few of these. I'll look into ordering a run of at least 10, and look into prices if ordering more also (20-25), as the price comes down a lot with more qty. Having them done in this engineering grade material and process is not super cheap but small part like this not super expensive. I'll try to get price down as much as I can, let ya all know.

Dean 802 522-6201

Randy Watson (RC Tach) makes them too, but maybe doesn't sell them individually. Here is his repop nipple compared to an original one (orange in color).

Dennis

Thanks, did not know that. They look nice, no need to reinvent the wheel if those are available?

gpguy, I don't know if Randy has any nipples in stock, or even sells them separately. He may just sell them with a hood tach purchase only. I would imagine you could make a run of a couple dozen and sell all if the price was reasonable.

I'd buy a couple if you do.

Dennis

OK I see what you mean, I did not see any on his website or ebay site either. Still working on lowest pricing here. I can make the sealing gasket and provide a rivet. Would be inclined to use a stainless rivet perhaps

SD455DJ, would you be able to provide a few measurements from that original?

gpguy, Certainly. It'll be a week before I can do that if that isn't too late.

Dennis

Hey thats fine, I will pm you, thx.
I'd like to make it work in the original heaterbox holes for folks that have an original case w/oem holes that need a replacement and won't have to re-drill etc.

So I am curious here on this subject, when did Pontiac start with the vent on the tach? I have a 70 that
is an original hood tach car, Feb build. It has never had the vent line on it.

My 70 has the vent hole in the heater box for the hood tach. When I first saw it. I didn't realize it belonged there. Glad I didn't weld it up! Would be nice to have the parts to make mine whole again.

My heater box has no hole and I have owned it since 1978, so was curious.

Tach Vent Date
 

I believe it was sometime in 70 that they started using the vent to help the condensation problem.

The addition of the drain fitting was a later in the model year addition. A late May Arlington built '70 Judge has been the earliest I've run across that was an original car which had the hood tach drain set-up. That particular Judge dud not appear to have been taken apart & have had the inner AC box replaced. Replacing the inner cover due to damage with a nicer used one, as well as replacing non functioning suncooked hood tachs was very common. Over a dozen years ago, before the BB crashed, i posted from time to time on V8buick.com. There was a good discussion going onnthat board about original hood tach usage, & I can remember contributing to the discussiion. The longtime Buick GSX preservation/restoration guys gave the opinion the Buick hood tachs with the drain fitting & hose setup did not arrive on cars until the '71 model year. Pontiac obviously was installing their version earlier & a reason I asked the question whether in original 70 GSX's were built that way.

I have a 1970 Oshawa built GTO Judge with a 06B, 2nd week of June 1970 build date, that has hood tach heat vent system for the UB5 factory installed hood tach on this car.
Pic attached

Our 11D Oshawa Judge has a factory hood tach and no filter ...just the dimple on the heater box

Gordon, can you read the PN stamped on the decal? Or, what was the needle color?

5657109 very faint but legible....needle is faded but appears to be orange