[bigblockv6]

The vacuum gauge on the big truck cluster is for the Hydrovac brake booster so in your case if it's going to be used in a light duty truck in won't work for that purpose. You can just hook it up to manifold vacuum as a mileage minder type gauge. The tach drive parts are definitely something you're going to have to search for, I've had a few of these in the past but have sold them off to other members but hopefully someone on this site has the stuff. There is a fitting that screws to the back of the cam then attaches to the tach drive so make sure that's included. As for whoever mentioned a tach for $50-$70 you're way off unless it's just a standard Sun RC-50 which resembles the GMC/Sun RC-5A. The RC-5A has the GMC style block numerals you won't find one of these for less than $300 and most won't include the transmitter box. I've seen some real outrageous prices on these tachs recently on ebay ranging from $450-$600.