hi guys, i do have a question on the fuel inlet fitting on my Rochester. What is a 1"-20 fitting, what are the measures? I called a few carshops and expert Shops in my area (Europe). No one do have a clue? What is the diameter and how many Threads? Thanks for your help

br Daniel

 

There is a repair kit for Rochester carb fuel inlets, includes a tap and helicoil. The size of the fuel inlet is 7/8-20 for carbs up to 1971 and 1"-20 for carbs after. Its actually best to send the carb out to a shop for repair to insure its done correctly.

These folks specialize in Rochester carbs:
http://www.sparkyscarbs.com/

 

Here's a site with parts:

https://quadrajetparts.com/quadrajet...-c-128_27.html

 

To answer your question, this is a Unified National Extra-Fine thread (UNEF) with 1 inch nominal OD and 20 threads per inch.

The attached table shows go and no-go dimensions.

 

What's the problem? Are you missing the inlet fitting?
The quadrajet parts site above has a selection of fittings. Note that the normal fittings use an inverted flare, 3/8" tube with a 5/8" nut.

One problem is for each thread size there are two different gasket types - either at the top or the bottom of the threads. You can see in the pictures that some use a smaller clear gasket and some use a larger black gasket. That needs to match the machining on your carb, otherwise there will be a small leak.