get a proper timing gun
a gun that shows the rpm and with the option to read/set advance in degrees

something like that
http://www.amazon.com/Equus-3568-Dig.../dp/B000EVYGV4

 

boeing, I just saw this, I think the rally-pac gauges don't look too bad, should be good for your '66:

http://mustangmonthly.automotive.com...all/index.html

 

I have a volt meter that also has a low rpm tach feature as well..It was part of a timing set kit that I got many years ago so you might look at your local parts store to see if such a thing is still available...........
Having said that I would just adjust the idle as low as possible and where the engine does not struggle to stay running when dropped into gear(assuming its an auto trans)..Once the idle speed is set to where the engine does not stall its just more of a personal preference thing anyway..

 

Long time ago, I attached a full-size tach to the A-pillar, down close to the top of the dash. This was before the current oversize (5"?) gauges started showing up, but it was at least a 3". If today I was to mount an aftermarket tach in a car that had no tach at all, I'd do the same thing.

Anyway, it'll be closer to your line of sight there than any in-dash or column-mounted gauge, without being enough into the windshield area to matter. I remember having to take it out for inspection, but only because it obstructed access to scraping off the old sticker (which you couldn't see through either) and applying the new one.


Norm

 

heres basically what my dash setup is

tach on the right large gauge pod and gas gauge on the far left

 

why the hell are rally pacs so pricey!

 

if you have electronic ignition do NOT hook up the green wire to the coil it will fry the tach instantly, if you have a MSD 6 series box plug it in the tach hole on the top.

 

Rally Pac gauges are cool, but I can't see spending that much for them.

I still think the best option for 67-68 is the tach that fits in the center clock provision.

I'm using this little tach that looks period styled and suits the car really well. Its been in my car since about 1994 or 1995.

http://www.jcwhitney.com/illuminated...wx?filterid=j1

 

I like this too.

 

Where did you get those gauges? And what did you do with the alternator gauge?