A65 Frankenstein Bolt

[TimHicks]

Does anyone know what this " Frankenstein bolt" is for?

[mikeg]

I assume you mean the "funny" looking nut. Those nuts, attached to a crankcase thru-bolt, have a stud on the end of them and they were intended to provide an attaching point for the forward cowling mount on a J-3 Cub. You will see them quite often. They can be replace with the standard crankcase nut. Properly torqued, of course.
Mike

[TimHicks]

Thanks, mikeg,
after I got your message, I went to the J3 forum and found this pic: