This kit is two copper sleeves to size down the bore of a 1.12 Autolite 4100 carburetor for improved throttle response. Each set is hand made and test fit in a 4100 carburetor, they are a tight fit but can be pressed in by hand.  However do to tolerance in manufacturing in the 60s some slight fitting may be required.  I had one customer (the first quote below) that the adapter was loose in one of his two bores (issue with the manufacturing of his carburetor) but the sleeves still functioned flawlessly.THIS KIT WILL NOT TURN A 1.12 CARBURETOR INTO A 1.08 CARBURETOR
If you want a 1.12 carburetor to function exactly like a 1.08 carburetor you would need to install these sleeves, change the jets to meet your engine specs AND change/modify the boosters.

What these sleeves WILL do without any other modification is improve throttle response and make it easier to install a big block 4100 on to a small block

Quotes from customers who are running these sleeves:"Instant difference in throttle response and almost completely eliminated the hesitation off of idle, very impressed.” "The Venturi reducers have been installed and I am very pleased in how the car is running."$29.99  +  $4.50 S&H

Link to my web site where they are for sale