JDR 4412 Gas Carburetors

Spec 1 
Designed for applications where the rules require the use of a gauge legal 500 CFM 4412 carb. Reworked and blueprinted to maximum legal tolerances, these carburetors provide much better throttle response and power throughout the rpm range. These are popular for SIMS, Limited Lates, Wissota, IMCA Sportmods, B-mod & Sportsman classes.

Spec 2
Designed for applications where the rules require the use of a 4412 carb, but  modifications can be performed. These include resizing the venturis, thinned throttle shaft, changing boosters, etc. 1 11/16″ base retained. On a restricted 2 BBL motor, these provide a significant advantage.
 
Spec 3 
Designed for open 2 BBL classes or where rules allow the carb to be heavily modified. This includes machining the venturi, throttle bore, throttle shaft, boosters, and reworking the fuel curve. These are “maximum gain” carburetors, and take advantage of all possible modifications that can be performed.
 
Spec 3 Extreme 
If you race in a class that requires a 2 BBL but will not be gauge checking the carburetor, this will give you what you’re looking for! This is the biggest, baddest, stock appearing 4412 on the market. A 1.750 throttle bore used to be the benchmark when it came to stock appearing “outlaw” 4412 carburetors. We’ve re-set the standard with these. With an even larger throttle bore, laser cut stainless steel throttle blades, and every flow enhancing modification that can be done, you’ll see a big increase in power over anything built for similar rules. Not only is the power there, the race track performance is unmatched. These are great on restarts and off the corners unlike some of the other “big” 4412 carbs that have been around for a while. No sacrifice, all gain!