Just dropped in my rebuit 1250 from 600 racing. I got 2.5 years out of my original motor. Not bad! Engine ran OK in my first race until the end of the race. Going through the corners the engine idle remained high and the engine would cough a few times out of the corner. Once the race was over and I was in the pits the engine idle seemed OK.
Today, I synchronize the carbs with my SyncPro and noticed that the manometer tubes did not go half as high on the scale as the prior engine. I understand that synchronizing is more about relative vacuum from carb to carb than absolute. That said, to me the absolute vacuum that an engine will pull is important. I used an absolute vacuum gauge that I have an only saw 10-12 inches of mercury. That seems low. A small block chevy will pull about 20 inches all day long. I used Jim's WD-40 test and could not get the engine to rev up.
Two questions:
1. What absolute vacuum should these engines pull?
2. Any ideas on what could cause this?
Happy 4th of July and thanks to all of the veterans!
Thanks.
