I've got a 279 truck y-block and I adapted an Autolite 2100 to it. It runs a lot better than the old teapot but a few issues.

It's a 1.14 venturi carb, and it seems a bit rich at idle. Is it too big? I know 1.08 is recommend for 292's and I can only imagine a 279 breathes a lot less than a 292.

I currently have 47 jets in it, and have not done a plug check. I'm at sea level. Are these a good starting point?

 

Howdy,

For some people, any modern carb is probably "better" than a Teapot!

There's little difference between the 279 and 292...... 13 cu-in
is not a significant difference. (My 2100 worked ok on my previously installed 239)

Idle mixture is controlled by the air adjustment screws unless you have internal leaks, leaking needle/seat, stuck choke, vacuum leak (or REALLY HUGE jets ), etc.......

I would suggest looking for and fixing the above problems if present before changing the jets..... Jets don't affect idle mixture much unless you have the air adjustment screw(s) out more than 2 or 3 turns.....

There's some info out there on starting points for carbs.
The following is a pretty good article on idle set up...... Technical Info

Holley also has a really good tech library.

Holley Performance Products Technical Library

Come back and tell what you did to fix it!!


Cheers,


Rick




Regards,


Rick

 

An Autolite 1.02 would be right for the 279. 1.08 OK, 1.14 too big. 47 jets in the 1.14 is about as small as you want to go. Jetting for the 1.02 would be 46. I have a manual choke 1.02 I think, if you are interested.

As a reference point the SBF 260s used 1.01 venturi carbs. Most of the time it seems that Ford was conservative on its assignment of 2100 sizes to engines. Therefore 260 can do well with 1.02, 289 saw 1.02s, 1.08 and 1.14. 292s came with 1.02 but do better with 1.08 and in some applications 1.14. 351s can use 1.21 or 1.23.

The booster cluster has a number of small air bleeds. If they arent clear problems will result. Pull it out and blow them, and each orifice, all out individually with a can of carb cleaner followed by compressed air. Dont loose the rod like weight and ball bearing when pulling the cluster. Also take care not to damage the booster gasket.

A warped Power Valve cap is common. It happens with overtightening the small screws, and allows air to pull into the bottom of the PV area, allowing it to stay open all the time. RICH. It acts similar to a blown PV.

Check the float level. Try dropping it a 1/16 inch and see if there is a better result.