There is a template out there that has the main hole and mounting hole locations on it. Get yourself a hole saw set and a six pack and do it yourself, lol. I replaced my tach a couple of years ago, and if you want original style, I like mine that I got from "the parts place". They use a screwed on assembly not glued and real glass not plexiglass. Works well and looks stock with upgraded internals.
https://www.youtube.com/watch?v=VSaytPFquVg&t=85s Does this look correct also I see a template for the 400 hood emblems for a 67 400 on FGF have a 69 not sure if its the same I bought a hood from ames pretty [censored] nice too except no holes drilled for the 400 emblems I need that template looked around dont see one for a 69 is the 67 posted here the same ?
Always check with Ames for dimension sketches. If it’s out there they prob have it. They will email it for free. I didn’t use a template. I had a drawing with all the hole locations dimensioned from the edge of the hood. I believe I got the drawing from Ames.
Its an easy job, with a good drill bit and new metal snippers. Buy the Hood Tach that goes straight to your HEI distro and does not require any mods to the wiring. Mine has worked fine for 17 years now. Two bright bulbs light her up at night.
'68 428 HO M3 Monster, 4-on-the-floor! Need I say more?