for the water temp...can I use the existing temp sending unit and just connect wire from idiot light to gauge ?
unknown. not a good idea anyways. even if the sending unit was compatible *when new*, it is now +50 years old.
do you really want to go to the hassle of installing a sparkily, fancy new gauge ... and then feed it from a part that's likely to fail soon? kind of a silly thing to cheap out on, don't you think?
for the alternator......how do I convert to gauge ?
alt gauge is just a voltmeter. should read ~12.5v when car not running ( static batt voltage ), 14v or a bit less with the alt spinning and no current draw ( headlights, stereo cranked, etc ). should NEVER read less than 12.2v, or you're running the battery down / alt not charging / short to ground someplace, better find it before it starts a fire.
i would connect a ground wire to neg batt terminal, pos can come from batt or alt. if you want to be more finicky, you'll run the pos wire to alt. although, hardly anybody bothers running a discrete ground wire from the alt to the battery ( they usually just ground the alt through the block ) so i don't see what the big deal is.
foe the oil pressure......I know run a hose to gauge but where do I connect to engine & what type send unit ??
Buick oil pumps for the SBB, BBB and v6 engines are all up front in the timing cover.
therefore, you want to pull your pressure reading from the BACK of the block. that way you can tell if you've lost a bearing / clogged up an oil path and make sure you're not starving the back of the block while still showing plenty of pressure on the front end.
http://www.buickperformanceclub.com/Oilmods.htm
