I guess David Vizard doesn't know anything.
Do you believe everything you read?
You shouldn't, make sure what you except as the truth is the truth, especially in all things mechanical
Cab, do you know who David Vizard is? If he states that ALL street cars should run manifold VA then I believe him.
I have read Vizard's book as well as Emanuel's and would like to make a few points:
David Vizard is a revered engine builder and an acknowledged Chevy big-block engine expert. Enough so that GM contracted with him. And most of his brand specific books center on GM engines. So that is where his experience lies. Not with BB Mopars.
Vizard's book was written a long time ago. And although some things are the same today, some things have changed since it was written.
I have not read Vizard's manifold porting recommendation in any other Holley tuning book. And certainly not for ALL engine applications.
Which brings me to a few questions:
Have you tried re-curving big block Mopar distributors to see if that if preferable to Vizard's recommendation?
What advantage do YOU believe manifold vac has over a properly curved distributor in our big blocks?
Do you not see the disadvantage of vacuum dropping off with throttle opening and therefore dropping timing out?
