Hello All, Can anyone tell me how much vacuum should read on a 1958-235 motor Thanks Richard

The shop manual says 17 to 21 inches.

Hi Chevnut, I have a 1958 235 motor in my truck that has been all rebuilt and When I hookup a vacuum gauge to the manifold ( With the timing ball on the mark), my guage says"Late Ignition Timing" in order to get 17-18 pds I have to increase the timing to the point that it won't start when it's hot, If I then set it back down it starts good but I only have 7-8 pds of vacuum. What do you suggest? Thanks, I appreciate your advise.