Thanks for all the input on this issue... I think that for now, I'll leave the cowl-spinner gap where it is. I can always close it in more if the spirit moves me. I do have two large area washers between the motor and the two top mounts.

Unlike 5ZQ, I was not able to set the spinner to .375 high relative to the top cowl. With the spinner flush with top cowl, I only had .25" clearance between the inside of the cowl and the ring gear.

On another subject, I'm tempted to paint now vs leaving my plane in primer........

Angier Ames
N4ZQ