Autolite 4100 carb ques

[Thomas C Potter]

I know this is not MM related, but some of you smart folks proably know the answer. Is the 4100 considered a SQUARE Bore carb?? I ask this here so hopefully I can get an answer soon leading to my purchasing a Speed Demon carb so I can get my '68 XL back on the road. Thanx. Please don't boog down this thread with stupid questions like what is a square bore!!

TP

[UncleLar]

The Ford Autolite 4100 is a "square" carb,ie all 4 throttle bores are the same diameter,as opposed to a spreadbore type carb like the Autolite 4300 and Rochester spreadbores which have small primary bores and larger secondary bores.
The 4100 looks a lot like a cheapened version of a Holley.

[RCSignals]

The 4100 looks a lot like a cheapened version of a Holley.

In fact, the Ford (before it was an autolite) 4100 carb, and it's mounting bolt pattern (which many today call a "Holley" bolt pattern) Made it's first appearance in 1957 for the newly designed single four barrel carb intake of the 312 Y-block. (yes, it's a ford innovation) Ford could not build enough carburettors on it's own, so it enlisted Holley and Carter to also build carbs for them The result was the four barrel Holley we all recognise today, and the Carter AFB. Who'd have thought it.