Mines the 1.12 600cfm.
Right now I'm running 48 and 55, and its hesitates pretty good when cold, when you stomp on it.
Seems fine when its up to temp.

I ask cause my stock 2v had 56 jets and i was wondering if I'm starving her of fuel?

 

It sounds like a lean hesitation from your choke deactivating too soon. If it runs good when warm then don't go to richer jets. Pull out a plug and confirm by the color the condition, rich or lean, or better yet, tune with with an o2 sensor.

 

Where did you find the genuine Autolite power valves? I used to be able to get the Ford rebuild kits that had them but since ford stopped manufacturing those I haven't been able to find an alternative kit that had a decent power valve, hence the mod for the holley ones.

 

I get my rebuild kits from Mikes carburetors.

 

Whats the tag #'s at the base of the carb? Should be left side front foot!

 

I'm having a heck of a time getting the gaskets to seal out vacuum leaks at the base. I tried Mr.Gasket #758, a nice, thick, insulating gasket, along with a coolant circulating spacer, but can't get the thing to seal. I may have to take the spacer to a shop and have it surfaced, or use a diff. spacer.

Any ideas?

 

If you get me the list off the carb... I can tell you what size jets, what the primary and secondary boosters are suppose to be and all that good stuff. Even what it came on.... Just trying to help...

 

Thanks for the offer. The carb is a C6SC. It is the 1.08 venturi, 480 cfm model. My source says it came on a 66 Tbird with a 390, a c6 auto trans. But I've never found a source that lists the booster serial number/letters for each carb.

It is going on 300 I6, so the oem settings only serve as a starting point. Thanks again. k

 

Have you checked for a vacuum leak at the throttle shaft? I have a couple of 4100s that I have had to get bushed because the throttle shaft bore was worn out of round and allowing air to get in under the throttle blades. I pulled my hair out trying to find the source of the vacuum leak until I discovered this.

 

Thanks for the guess. I rebushed the shaft myself. I have checked and it is not leaking vacuum.

It was leaking through the hot idle compensator, and that part is obsolete, so I plugged it. I also changed the base spaces and gaskets. Now it will not idle at all under 1500 rpm. When I manually pump the gas, the rpm's go up, and stay up for a few seconds after I let off.

Now I have the carb apart again and am going through it all once more with compressed air.

Note: It is impossible to find a base gasket that seals. All the Holley gaskets leave a bit of the outer edge exposed. The Mr. Gasket #58B looks promising. If it doesn't work/fit, I'm going to make my own.

If anyone knows where to find a gasket that fits, outside of a kit, please let me know. k

 

Have you tried one from Walker?

https://buy.walkerproducts.com/carbu...omponents.html

They sell the parts from their kits individually so you can pick up the flange gasket for $1.07. Not sure what shipping is though.

As far as the vacuum leak, the only other thing I can think of is the base. I know on my eddie intake manifolds I have had to flip the factory pcv spacer upside down to get it to seal correctly without having to buy the adapter from edlelbrock.

What about your power valve? Is it defective and enrichening the system when it shouldn't be?

 

The only ones listed are C6SF-A and C6SF-C

Assuming its a C6SF-C carb Primary booster is a "PK" stamped on the bottom and secondary booster is a "F", Jet size are 47F and 67R

 

Here is my tag # C6AF-L
1.12.

 

OK... This was on a 352 FE... Primary Booster is "KD", Secondary booster is "BA", Jets 48F/ 55R

 

What I have is two 4100's. The one I bought on ebay was so bad that I needed another just to make one good carb. Both are the big block 480 cfm 1.08 venturi size.

Boosters: The C6A F had what looked like performance boosters, judging by the size of the air bleeds and the diameter of the end of the emulsifier tube, if that is what you call the tubes that stick down into the carb body from the boosters. The primary was DK, and the secondary was F.

Since this carb came off a 390, I thought it too much flow for my application. So, the C6SC I took apart had a TD primary booster and an FT secondary. The restrictions in the end of the tubes were much smaller, like those found on a 289 4100, so I thought they were be better suited for my engine. I swapped them over to this carb, the C6AF.

I've noted that it is also difficult to find a base gasket for the 4100. I don't like the open plenum gaskets supplied by most kits. I noted the oem gasket on the Tbird from which I removed the C6SC was 1/4" thick, tapered from end to end, with a pcv inlet in the primary side. It also had each primary bore separated, and the secondaries joined, just like Felpro 60046. As an insulating 1/4" think gasket between intake and spacer I'll use Mr.G. 758.

I'll see where that will get me.

I have redone the carb once more, blowing out the boosters and all passages. Hopefully it will idle this time around.