[John V.]

Posted this in the '64/'65 GTO forum. Looking for any additional help.

I set up the complete '64 tripower with what I think is an original vac secondary linkage. I hedged my bet and purchased the mechanical linkage kit from Dick Boneske, stored away for now.

I've been unable to experience the vac linkage because of what seems an impossibly simple thing.

Problem is, in order to connect the small link from the Vac Diaphragm Can arm to the rear carb, the end carbs have to be pulled open a tad. Not good.

Trying to figure out what part is wrong.

I made crude measurements of my stuff. Here is what I have, hoping somebody here has known properly fitting '64 vac linkage parts they can take measurements of to compare.

For the small link itself, I measure 27/32" center to center on the link "arms" and 1" from outside to outside of the arms, with the rod material being 5/32" dia.

I estimate it is short by approx. 5/32" which seems like a lot. It has a "hump" in it that I'm sure is factory. Either I have the wrong link, or the problem is elsewhere.

The diaphragm can assembly that I had seemed correct. I sent it out for rebuilding.

Essentially, the guy pried it open, replaced the diaphragm, replated it, and somewhat crudely crimped it back together.

When I received it back, the actuating arm that sticks out of the can seemed 180 deg rotated as it was not "centered" in the hole. I should have taken a pic of it before sending it out but didn't.

Seemed odd that a guy that "knew" what he was doing failed to get it right the first time. But I sent it back and he disassembled it again and rotated it for me so that the actuating arm is centered in the hole.

The diaphragm mounting bracket seems correct also. I acquired the can complete with the bracket years ago. The bracket looks just like the one in the factory illustration of the Tripower in the MPC.

It really only installs one way it seems. And I don't see that it is adjustable without butchering it.

I haven't been able to contact Dick Boneske for awhile but when I asked him for advice, he shared some pix showing how the parts should fit together.

The rear carb lever on mine is stamped RP 27767. The one in Dick's picture looked to have the same stamped no. so I think it is correct.

So that leaves the arm attached to the diaphragm.

Since I had it rebuilt, I can't be certain the correct arm is attached to the diaphragm.

As best I could, I measured the straight length of the arm at 1-13/16" from the base of the L shaped arm (where it is riveted to the diaphragm) to the peak of the rounded end just forward of the link hole. The center of the hole would be about 5/32" short of the peak.

Looking for somebody to measure the link arm on a good diaphragm can.

I suspect that is where my problem is.

Conceivably the bracket extends too far rearward but unless there were similar brackets with slightly different dimensions, that seems unlikely.

Crudely measuring the bracket, I got 3-3/16" from the face of the diaphragm can to the center of the forward mounting stud if somebody has a bracket and can check that dimension.

Hopeful that comparing my measurements with a known set of good parts will make it obvious where the problem is.

Some pix attached show what I've got.