Just another aside to Jim Blair: You asked about the power valve on the MC2100... I don't know if the 16" Hg measurement I quoted was correct, I only know that there was a "1 6" stamped on the side of the valve, with no other markings, and took that to mean the level of vacuum at which the power valve would open. Could be 6", I don't know. In order to find out whether it was flooding out at that problem point, I'd probably have to hook up an O2 sensor and watch the meter as I feathered it in and out of that range, and see if it jumped suddenly rich or lean. I'm starting to think, now, that the problem is partly the carb and partly the engine, since the Carter sorta does the same thing too, just not so radically. The cam is a 252h from Comp Cams, which is listed as a 'mild' cam, with a slightly longer duration and 4* advance designed in. I recall setting the timing chain gears to 3* advanced too (not knowing about the cam), so I may be just running out of vacuum when the carb needs it. ____________________________________________________________________________________ Sponsored Link Mortgage rates near 39yr lows. $420k for $1,399/mo. Calculate new payment! www.LowerMyBills.com/lre _______________________________________________ AMC-List mailing list AMC-List@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list or go to http://www.amc-list.com