I know this has been asked a million times and I have done a search to see if anyone has a template or anything useful as to know where to drill the hole for a hood tach and the only thread it really brought up was one that the links didn't work at all so it really wasn't much help other than saying that a 4 inch hole will work. Does anyone have a template that we can maybe print off that we can tape to our hoods so that we can drill the hole in the right place?
...there are multiple issues with finding correct template. First is that your question has been asked from earliest days of forum, and the software running the forum was changed along the way, resulting in broken links to posts from earlier forum software, as you experienced. Secondly, there have been several aftermarket tach makers whose templates include a larger hole (original AC was 3 3/4"), and these measurements have found their way into answers. Third, original AC tach was factory installed and available thru dealers. Since it fit multiple GM cars and years, lots of templates were floating around. I have never personally seen an original GS template, so have no idea whether they were GS-specific, or as is often the case, made with measurements for multiple applications. Finally, without a known original template for '70-'72 Buick A-bodies, the only way to know placement for sure would be to have someone with a documented factory-installed tach, remove tach, take accurate outside measurements from rear edge of hood at tach hole centerline to upper edge of tach hole (easier than to center, but either would do), and likewise from left edge of hood. The values I have for a 3 3/4" tach hole are 15 1/8" from rear edge and 11 1/2" from left edge. Caveat: IDK if these measurements are correct, perhaps someone could verify. Using a sheet of paper at least 14 X 18, label 2 adjacent edges as "rear" and "left," and make a template. Starting at corner between "rear" and "left," mark 17" down "left" edge and 13 3/8" across "rear" edge. Center of tach hole is at intersection of lines at marks. You can make tach hole whichever size needed, it will be located "originally." You'll use your tach for mounting hole placement, and if it's an aftermarket, you may need the larger tach hole...
Be sure to tape a LARGE area around the proposed hole before drilling. Any stray hot metal bits will melt the clear coat. I had a few strays that went surprisingly far. I used the template provided in the aftermarket kit, but I moved it just a tad because it didn't look right to me. (the view from the driver seat is best to check and compare to others you have seen, but check all angles til you are happy) I also would bet if you measured every factory tach location there might be small differences. If you have an aftermarket tach, the manufacturer would probably be able to send you a template.
