What year 261 carburetor?
There were at least 2 styles of 54-63 235/261 truck carburetors (more 235 styles if car carburetors are included):
- one style allowed attachment of the air cleaner with a clamp around the base of the air cleaner - clamp around the "throat"
http://www.carburetion.com/images/carbid/r1-bc.jpg- one style allowed attachment of the air cleaner with a center post above the "throat" of the carburetor
http://www.carburetion.com/images/carbid/roch1.jpgYou might want to indicate if your carburetor appears to have a manual choke or an automatic choke.
center carb here:
http://www.carburetion.com/images/Inventory/R1carbs.jpg
