Thanks John, I'll check it out. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire

John,

What are your thoughts about using a restrictor plate(ala Nascar)with a 1.12 4100 on a stock 272?I agree with you about the 1.12 being too big for Y-Blocks,other than one of the big inch racing engines.

 

Paul,

Boonville,MO

Tom,

I'll let you know if and when I get it done and on the car.This time of year there just doesn't seem to be enough hours in the day.I retired last january and have been busier this summer than when I worked 90 hour weeks.I should have it going in few days.

 

Paul,

Boonville,MO

Paul:

I've never tried that, but it would not change the cfm of air going into the engine at less than full rpm.  The way I understand it, using spacer plates under the carb will fool it into thinking the engine is bigger, but I can't remember whether it is the open plenum spacer or 4 hole spacer that does that.  Help, anyone?  We seem to be going through a phase here repeating 50 year old history.  The biggest mistakes made on street engines have always been overcamming and overcarbureting them.

John

John - "The Hoosier Hurricane"

Check out this discussion forum on Autolite 2100 and 4100 carburetors: http://www.ytmag.com/ford/wwwboard1.html .  Its 2100/4100 guru is Bill white.  After studying it and asking a few questions, the answer to using a 1.12 venturi carb on a Y is that it WILL NOT work.  The Autolites were tailor made to the vehicle, meaning its motor, trans, gearing, weight, and rpm range.  When there is a correct match between the carb and vehicle the Autolites work great, are simple and reliable.  However they are not very tunable, and were never meant to be.

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

Didn't Holley make a version of the Autolite carb for a while? I think it was the same basic design with a removable top cover and annular discharge boosters.

Best regards,



Paul Menten

Meridian, Idaho

This would be the Holley model 4100.  Basically a good carb but never really caught on with the aftermarket crowd.

Lorena, Texas (South of Waco)

Paul,

      Re the question on the restrictor plate. Like John said the issue is the air flow at low RPM. The Restrictor plate won't change that. All it'll do is restrict the amount of air at higher RPM. You have to have enough airflow through the primary side of the carb to create a signal for the fuel circuits to work accurately. If you don't have that because the carb is too big, nothing short of fuel injection is going to help.

Frank/Rebop

Bristol, In ( by Elkhart) 

After thinking a little more about it,you and John are right of course.So, for now I guess I'll stay with my stumbling Holley.

And the tall spacer fooling the card into thinking it's a larger engine is right also.I ran into that on a circle track car when the rules required a two barrel for the limited late models.I bought a C&S carb that flowed 925 CFM and it was too much carb for my 383 until I put a 1.25" two hole spacer under it.With that spacer that thing came off the corners like a rocket.

 

Paul,

Boonville,MO

ok, so I have a further question then, does anyone know what the proper, or ideal percentage of butterfly size to venturi diameter is??  Would shrinking up a 1.12 venturi in theory require a smaller butterfly? I would think for ideal throttle response of course.  But for adequate throttle response?

I personally have successfully increased the secondarry venturi on my 1.08.  I know the stone I used is right at 2.0.   With the transitioning work I did to clean them up, (more on the bottom) it could be a fraction more.  The trottle plates for the secondary's are obviously too small for that size venturi. 

Pony carbs claims they reduce the primary venturi on their 1.12 spreadbore to 1".  Do they leave the throttle plates?

Kevin