In Below text ;pertaining to the 340 carbs What is nozzle RI 738 ?
A "COLD" Manifold with Air Cleaner

Throttle Side Diaphragm Side
Front Carburetor PVCR .086 .073
Center Carburetor Jet #64 #64
PVCR .046 .046
Rear Carburetor PVCR .086 .073


Nozzle #Rl738 installed in diaphragm side of front and rear carburetors.