40 thousandths makes a big difference

I planned on replacing my spark plugs this weekend and pulled my R12yc out in preparation, grabbed the new box and they were the wrong plug, RC14ES so I regapped the old used R12's which were out to .075 and closed em down to .035. What a difference it made, much better power and response. I'll check my mileage on Thursday when I fill up again and see how much. I was down to 15-16, hoping it goes back up to 20.
Did clean out the local advanced auto this evening of R12's though, bought all 24 of them they had in stock.

Yea the gap makes a huge difference. Just make sure you check them all. DON"T trust the one's that are supposedly pre-gapped. I just put new ones in mine and it seemed to smooth out my idle a lot.