'74 360 block here...checked the hole diameter and it looks to be around .300-.310, however several on-line sources reference a 0.275" diameter pin (Mancini Racing), and yet there is the following Mr. Gasket part which is 0.310".

Heck, this Pioneer Automotive set is a steal at $11 for 25 pcs!

So what the heck is the right/correct dimension?

I've never seen a wobbly dowel pin ever, so that 0.275" diameter seems not right.