Crankcase evac. Question?

famous bob said

interesting. before I tore into my 505 to check bearings (for the hell of it), I was checking vacuum the last time I drove it. It had more than I was expecting , 8-10- at idle, as hi as 16 at other times. this is w/ a .628 solid roller, 254-260 @ .050.----- the inside of the engine looks great, but after pulling the plugs, I noticed # 7 was colored like a paper sack, the rest were soot black, -------- comments ???

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Wow! As YR said that's impressive. To be honest I have never measured any other than mine so I don't know what an EVAC would pull in other combos. I'm sure there are several factors that influence how much vacuum it pulls. Sooty plugs is rich. Could be as simple as the idle is set too rich. Could also be the main jets. You really need a wideband A/F meter to tell in what circuit(s) lies the problem. First and easiest thing to do is try leaning out the idle when it's warmed up and in gear. If you can't lean it out without it running rough it's probably in the high speed circuit