Building up my 68 340

I was gonna get the ld340 but then I read where the RPM Air Gap was just as good. Then I found out my dad had one on a 340 he has sitting. He will not be using it for a long time and said I can have it just got to replace it when he needs it. If I know him and his projects i have a long while.

If any of these are worth the added expense I will buy one. I will look into that and thank you for the info on the cam.