Is the distributor hole of the 426 hemi the same diameter as the hole in small blocks

Id have to see that to believe it. I know the spacer is made for a RB distributor in an B block, but you'd have to get lucky making the short B distributor fit in an A block unless it just barely made contact with the drive gear. Not to mention the wrong rotation.

I never wouldda believed it either until I saw it. And here's the thing. "I" tuned it SEVERAL times and DIDN'T notice it. Now I know why I couldn't get it to run "just right".