Carter AFB Competition Series vacuum port

Question on an older Carter Comp Series carb. I need to know if this is a full-time vac port on the front of the carb (see arrow). Thanks.

 

Blow air into it, and if it comes out below the throttle blades it's manifold vacuum; above would be ported vacuum. If you're looking for a place to connect your vacuum advance, you want manifold vacuum...

 

That vac port does not work at idle. I ended up installing a 1/2" spacer & added a nipple to it

 

Interesting picture!

The OP states that he has an older Carter competition series carb; and indeed the stamped number APPEARS to be 4758s, which is the number for a 500 CFM carb with a MANUAL choke. The picture clearly shows an automatic choke housing???

Jon.

 

Good eye.

I've since removed it & installed the original manual choke linkage & shaft

Here's the front carb.



and the pair together....



The 500's were a little small on my 455 Olds though.

http://59chevypickup.webs.com/photos/undefined/0004a.jpg

Hopefully they will be ok with my new tunnel ram 355 SBC

 

TJ - for a strong street 455 Olds, try a pair of the 4759s 625 CFM. As you probably know, Carter did not release a "no choke" version of the 625, as they did with the 500 and 750 sizes. However, it is very easy to remove the choke and plug the holes with aluminum drive plugs; or do as I have done on my very strong Ford 390, use chokes on both. For street application, I really believe chokes on both are preferable to only the choke on the rear.

I ran the cable to the rear carb, and cut a piece of 1/16 steel rod to run from the rear to the front. Both chokes, like both carburetors, run simultaneously (no progressive linkage).

Jon.

 

You don't want constant vacuum for the distributor. Your advance would be constantly working. The more you crack the throttle the more vacuum it should pull for distributor. That way it eazes the vacuum advance to full.

 

I think mine has port for pcv & vacuum advance port plus a full time vacuum port.

 

There is also a port in the back plugged off for brake booster.

 

Wrong

 

Actually ( this is gonna start a s##t storm ) the 1969 mopar shop manual states that "tube fitting" is ported vacuum and is for distributor advance on the 2-4 426 hemi, 383 4 barrel, and 440 4 barrel.

 

Aren't those the same as the Edelbrock Carbs?

If So, on the Edelbrock, that's a timed vacuum port.



Here is a link to the Edlebrock Owners manual.

https://www.google.com/url?sa=t&rct...s-manual.pdf&usg=AOvVaw1cnAP1eKnlha6RzRxNv6ng

And here are the rebuild instructions.

https://www.google.com/url?sa=t&rct...350-1921.pdf&usg=AOvVaw0W4ckAmv67Swbq_QpiKD1X

 

Ported vacuum.