there should be a vacuum can under the hood, and a check valve close by on the hose, and that is there for that reason, it stores vacuum for full throttle to maintain vacuum for heater controls

 

Thanks for replying, I have checked the vac cannister and check valve and it had no leakdown after 5 min. even tho the engine runs great and has good compression, I am satisfied at this point that this particular engine is only capable of producing 13 HG vac.at idle. when doing smoke/pressure test i only found 2 really small leaks.
If anyone is interested, yesterday I found a Red 1993 f150 Lightning on north Mississippi Craigslist, looked perfect for 8500.00

 

I thought I could leave this alone, but being the **** retentive type I have not been able to get it off my mind. I just ordered and received a new Vac/Fuel Press test gauge. Guess what? My installed vac gauge still shows 12 HG at idle and the test gauge shows 22 HG,normal. I sure wasted a ton of time and effort on a non problem, but now my OCD brain can rest.