Advance curve wanted.

Alex,

Ported vacuum was not utlized untill the real late 70's early

THAT is the main reason for the ported vacuum. NOX goes up when the timing goes up! As far as the emission folks are concerned....that's a bad thing! As far as performance goes, more timing (within reason) is a good thing.

We've talked about this before, that's why I sent you that "expert/designers" point of view the other day. Ported vacuum is an emissions tuneup, not a performance tuneup. The Studes combustion chamber, ignition, cam shaft and lack of modern fuel injection make it NOT an emission design engine.

Direct vacuum (the old way!) does work.

I'm not sure what you and the other "Mike" mean by direct and ported vacuum connections. Some people have called the connection on the carb, above the throttle plates, the ported vacuum connection. At any rate that's the one you should use. Don't use manifold vacuum. Is that what you meant by direct? I understand the new replacements for the AFB may have more than one choice for above the throttle plate vacuum, but it's pretty simple on the Carter WCFB or the AFB used by Stude. The advance specs for R1 & R2 are in the Avanti manual. Did you really want the R3 info; or was that a typo? Mike M.

Hi Mike,

I liked the page and have copied it into Word form so I can print it out. I do question his claim on the history aspect though Every Chevy V8 I can remember had ported vacuum and I had a 57 Chevy and later a

Either way, if I'm going to experiment I would like to know what stock was.

There's good info at Bob Johnstone's site:

Looks like Studebakers came with ported vacuum.