I know this has been covered but I can't find anything using the search.

I will be buying a hood tach for my 69 and wonder what others have to say about who to buy from. I have had my best luck with Ames but at $209 their tach is the cheapest and may be of lesser quality than some others.

Also I need one that works with a GM HEI.

I would appreciate any advice from others who have been down this road. Any insallation tips would be welcome, is the 3.75" hole standard for any "stock looking" hood tach I buy? Thanks