General Category > Quadrajet Carb Talk and Tips

Ported or manifold vacuum vacuum advance?

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jvmagic:
Hi,

I have a 79' TA (403 olds) and my carb seems to be running healthy (rebuilt last year) and the car runs even better after recently recurving the advance on the distributor. I was told to connect the vacuum advance to a ported vacuum. 
It seems like its 50/50 as to where to connect.  Any ideas/experience?

Thanks in advance.

Cliff Ruggles:
How was the distributor recurved?

Lots of opinions on vacuum advance.  I use ported for most engines here, unless some poorly educated engine builder stuffed a Comp XE, Thumper, or Thump your Muther cam in it on a tight LSA and didn't raise the compression to compensate for all that overlap.......LOL.....Cliff

jvmagic:

--- Quote from: Cliff Ruggles on February 07, 2019, 03:05:04 AM ---How was the distributor recurved?

Lots of opinions on vacuum advance.  I use ported for most engines here, unless some poorly educated engine builder stuffed a Comp XE, Thumper, or Thump your Muther cam in it on a tight LSA and didn't raise the compression to compensate for all that overlap.......LOL.....Cliff

--- End quote ---

I was recommended a builder that has a Sun machine. The advance starts at 1k rpm and 34 degrees in by 2800rpm + 12 vacuum.  What a difference!

Cliff Ruggles:
As long as it was done by a professional and not by a hobbyist using a Mr Gasket spring/weight kit.

Yes, done correctly you will notice improved engine power and performance across the entire load/speed range.

Done with a cheap offshore spring/weight kit it's nearly impossible to keep some of the advance out at idle speed and the parts are junk.

I only use OEM components here and have never been able to get a good end result with anything the aftermarket has to offer.

I'd like to have a nickel for every cheap POS advance curve "kit" I've removed and replaced with stock components that we "tweaked" instead, could retire tomorrow!........Cliff

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