Guys, according to Anderson's BB the Fox 35 started using a 6 bolt head in 52'.
My first engine was a K&B .29S stunt. Given to me in the late 70's by my mentor and I still run it today.
I am 33 so I am afraid I wasnt around when it was actually produced.
Andrew Coholic
PS. this thread, regarding converting RC engines to CL.... I have been an avid hobby machinist for quite a few years. I have converted many, many engines to CL - just make friends with someone who owns a lathe. Its so simple, the venturi, spraybar and needle can be made up in an hour. Never rely on anyone else again!

Get a small hobby lathe...