quick question. . .if i'm putting in a second gauge under the accessory 52 mm clock (which i am), can i power and ground the new gauge from clock wiring harness? (i.e. have them both wired to the harness)

Yes, for sure you can gang them and share hot and ground as well as light, just like the harness that comes with the triple turbo gauges does the job.

Sort of.

The clock gets a constant hot and a ground, and a dash light wire.

Constant hot might not be suitable for other gauges. For example, if you were installing an oil pressure gauge, you might not want a constant hot. There isn't any need to read o/p with the engine off :)

A better choice might be a wire that is only hot when the key is in I, II, or both. Example: the factory wiring in the Turbo for the voltmeter is only hot when in position II.

If you ganged it to the clock constant hot, the voltmeter would always read. Not that this is a bad thing, but it is one more (teeney tiny) drain on a battery that is not being charged by the alternator.

what if i powered it using the wire from the clock light?

You don't want to power the gauge by the clock light. You should only use that wire (brown IIRC) to power the light bulbs in the gauges, because it all comes off that rheostat. Oh yeah... if you powered a gauge off of the clock light, then your gauge would only work when your lights are on. :)

If you want a source of power on in position II, just check your wiring diagrams and run a line off of a switched fuse. It will only take a few minutes to do.

Greg