On a 360 stroked to a 410, what should
the clearence be between the rod bolt and the block?

Steel rods ?

yes steel rods

I think .050" would be more than enough. Individuals have gone with as tight as .030 quench on the other end with all the rod stretch to be accounted for tho some of that is for piston rock & you wouldn't have any stretch really on the big end. It'd be easy to notch the cyls for that amt of clearance.

Always used a paper clip as a gauge, or about .060.

It's not rocket science. I just eyeballed mine and have no problems. If you use H beam rods no grinding necessary.

I used a zip tie - that measured out at .060 and it worked great - you can hold it loose and stab it in there or wrap the rod in it and spin it to see if it clears.

60 should be more than enough. If your crankshaft is deflecting that much you've got real problems. Shoot, how tight do people make crank scrapers?

R.