Anyone know maximum diameter prop I can run on -2 Imco lower with SCX upper?

I'm sure it is close to the same as a Sportmaster lower, which is 15.25" max diameter. If you try and spin a 15.5" prop, it is going to hit the cavitation plate.

Call IMCO....

From the center of my prop shaft to the upper housing is 8 inches. This is with a bravo 1 upper hope this helps.

I have 15 5/8” Maximus props on my sportmaster lowers

What cavitation plate do you have on your drives? With my -2's and the sportmaster cavitation plate, I have at most .25" of clearance between the tip of the prop and the plate, I think the gap is closer to .125". There is no way a 15 5/8" will turn on my drive without striking the plate.

The IMCO plate mounts on top of the cavitation plate on the upper vs the sportmaster plate mounting below it. Is it possible that your props were cut down to 15 1/4"? When I had BBlades lab a set of Maximus props for me last year for a -2 Bmax lower, he said the diameter would need to be reduced to 15.25". In the hub though, there are no stamps for diameter or pitch, only the BBlades stamp.

All the bravo quattros I can think of are running 15 5/8 diameter with sportmaster or imco lowers