Hi Shake and Bake, I made a template as well and I think I am close, but I don't have a hood to reference. The good thing is that these were dealer installed so no 2 are perfectly matched. I am having trouble reading some of your numbers.
The rear most 'rivet' hole: I think I read 9 3/4 to the side edge of the hood, but not sure about the rear edge. Is that 15 5/8?
The left most stud: I can't be sure about either of those numbers
The right most stud: Looks like 12 inches to left edge of hood, but I am not sure of the distance to the rear edge of the hood.
I think I know where I am going to place the tach, but I would like to do a sanity test with your numbers. One final question, the left and right stud - if I were to place a framing square on the left edge of the hood, they would be in line, right?
Mike, sorry about the sloppy writing....I originally made the template and then took the photo for my own reference because I like to be able to double check my work. I should have taken time to improve my penmanship so I could share the photo with others later.
I believe the dealers had a template to follow whenever they were installing a hood tach. I have seen the instruction sheet for Firebirds but haven't seen one for a GTO but I presume they existed. Even so, it's reasonable to think that each install was slightly different. I have compared the location of my dealer installed tach to a factory hood tach car and the two were very close. If memory serves....the side to side dimension was dead on and the front/ back was 1/4" difference. I decided to match the dealer installed location exactly.
The rivet hole dimensions are 9 3/4" from left edge of hood and 15 5/8" from back edge of hood without the stainless molding in place.
Left stud dims are 7 5/8" and 13".
Right stud is 12" from left edge of hood and 12 3/8" from back edge of hood.
I don't think the two studs are perfectly square....I will check when I get home. If memory serves....I think the tach is just slightly rotated counter clockwise when viewed from above, but I will double check that and report back.
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