Regarding main weber jets of course.

I just got a few sets larger and smaller than what I got now. Just wondering though.

Is it thousandths of an inch?

I'll try again.
A 145 jet flows the same amount as a perfect 1.45 mm hole.....perfection is rare in this world, but they're prolly pretty close to the listed size.

Beware of "other than new" jets as jet reamers are widely used.

A set of jet gauges is the only way to get them perfectly suited...

half sizes are not generally helpful with webers or dells but with the Solex p11 they really are....

Next race watch those EGT and take a timing light to the track with you. Call me between runs and I'll teach you how to tune BY EGT.

Buy a Barometer too.....