Quote below is from IMCO installation manual.

9. SCX Drive is 19 7/8” from crankshaft center line to prop shaft center line (2” shorter than standard Bravo). SCX4 Drive is 17 7/8” from crankshaft center line to propshaft center line (4” shorter than standard Bravo).

I am 100% sure you are WRONG.

SCX upper is 2" shorter.

This is my set up.
IMCO SCX upper standard SC lower with standard vertical shaft. Propshaft is 2" higher than standard Mercury XR.
If you want a real answer to your question and not a bunch of guesses, call Fred at IMCO.

SCX-4 upper is same dimensions as scx except for the cavitation plate that is bent up (lower to upper bolt pattern also different) to allow for the -4 lower prop clearance. The lowers are the difference between them. But yes a scx with a scx lower or a scx with a -2 sportmaster or -2 sc lower make the same x-dimension as a bravo with a -2 lower.

Those are -2 lowers pictured, not standard lowers

correction: Those are standard lowers, angle of cav plate tricked me. So your setup is the same X-dim as a standard bravo setup.

I was just talking to jeff Harris to confirm. He said the scx4 is -2 in the upper -2 in the lower. Regular scx upper and lower is -0 in the upper -2 in the lower.

But in any case silvergts is wrong lol

Don’t want to beat a dead horse here but the scx-4 upper is the same dimensions as the scx (obviously the splash plate is different). Otherwise it would not fit in the gimbal ring. The scx-4 lower is 2” shorter than a scx lower, which is 2” shorter than a standard bravo/sc lower

I did the conversion last year and checked with imco 2 times.
The SCX upper is the same height.