Update: The new flywheel that I bought online does not fit my engine... it's got one dowel pin hole and it has a larger diameter ring gear, and the bolt pattern is larger. Probably fits a V8.
Now I get to pay return freight- yay. The parts listing said 1958 4.3 liter inline chevy 6 168 tooth ring gear. I thought that a 4.3 is a 261 cu in. I guess not.
Sending the flywheel back.