vaccum

[slyfox]

Hi, i would like to know what the vaccum reading on the intake should be on a 383 4 barrel, holley carb.750, on a rebuilt engine.  thanks Sly

[A383Wing]

Depends on the cam, compression ratio, plus a few other factors....usually rule of thumb is 15-19" for a good start...

[c00nhunterjoe]

lol, yeah the stocker the engine the more idle vaccum you will have. we wont even talk about my idle vaccum 

[Ghoste]

So what is yours pulling slyfox?

[firefighter3931]

Also worth mentioning ; the initial timing has a large impact on idle vacuum. 


Ron

[c00nhunterjoe]

indeed, good call

[Purple440]

Hi, i would like to know what the vaccum reading on the intake should be on a 383 4 barrel, holley carb.750, on a rebuilt engine.  thanks Sly

It's probably different for any given engine build.  Just tune the idle mixture and initial timing until you get the most you can.  I like to set my idle speed screw to a low RPM, then see how much I can get out of it back to around 850RPM.  Gives a crisp throttle response for me anyway.

[slyfox]

Hi, Thanks for all the info.  Sly