Which wing nut is used on C1's

[John F.]

Re: Which wing nut is used on C1's

Here is an original sitting on a dime for comparison.

[David B.]

Re: Which wing nut is used on C1's

Lets attempt to put this thread to bed! Forget machine marks & photos which only give a general idea of configuration. The following is a quick study and NOT infallible:
There were 4 wing nuts used from 1955 thru at least 1962 and beyond (research time limited).
1. Type A 117204 designed 8/16/34
2. Type A 126177 designed 6/19/36
3. Type B 3736162 designed 3/13/56
4. Type A 3744846 designed for '57 air box only
5. Type B 219281
Number 1 and 2 are the exact dimension the only difference is 117204 is chromium and 126177 is cad/zinc platted. Both were used on all production GM models thru at least 1962 and perhaps beyond. It appears special type B 3736162 chromium was designed to eliminate the use of a washer and was used on 2 X 4 carb engines from late 1956 thru at least 1962. #5 Type B 219281 is a pre 1955 wing nut and it shows up in the 1960's parts book as replacing 3736162. Their dimensions are very close but not the same which probably causes some confusion in there use today. Check your AIM for the year you are interested in.