Follow up:
i ran a test yesterday while the weather was warm.

by chance, last year i had measured the manifold vacuum when i put in my PCV valve. this was a help as it gave me a base for this test.



after warming the car up i pulled the air breather and left the top off of my box. basically free air in with no possible restrictions. i took vacuum readings at 1000, 2000 and 3000 rpm's. all three readings were exactly 1" of HG off from my base readings last year with the stock air breathers in place. next i did the same test with the top on the air box but no filter in it. i wanted to know if the box itself would show restrictions. for this i got the exact same readings as with the top off. So i concluded that my box / hose was not restricting the air flow.


Then i put the new Spectre air filter in place and ran the same test again. oddly enough it was a half inch off the free flow readings but a half inch better than the stock air breather readings for all rpm's. (exactly in the middle of the two) From this i concluded my system is no worse at restricting air, and certainly no worse at filtering it, than the stock system. In fact it seems to be a little better.


Important to note none of this is under any load. i think it would be really hard to control all the variables. wind direction, behind another car, slight hills, where i actually give it some gas... All effect vacuum readings. not sure how accurate i could be.


what i don’t know:

  1. would the result be the same under load?
  2. differences in air temp going in the carbs vs stock filters?
  3. will there be any “ram air” effect at highway speeds?
  4. will this help engine temps at stop lights?
  5. will i need to change the fuel mixtures in the carbs?