Quote:
Originally Posted by biagionim
Ok so let me see if I got this right? As throttle in creases manifold vaccuum should decrease and so should the vaccuum advance right? Well if I have that right there something going on with my motor because manifold vaccuum does not decrease when throttle is applied it only goes higher! Upwards of 20"! Does this sound unusual or did I misunderstand
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You're fine, and the vacuum is behaving normally. The highest vacuum will occur at higher RPM and no load.
You could install a set of Rhoads lifters to help the torque curve, but they're about the same price as a new cam. Even though I really like my Rhoads lifters, I'd opt for the cam in this case.
One thing that does get over looked when making a cam choice is how cubic inches affects the idle characteristics. What is an almost imperceptible lope in a 455, turns into a nice lopey idle in a 400, and turns into a low vacuum, finicky beast in a 350.