Longer rod = more leverage on the crank and less side load on the cylinder walls.

Longer rod = shorter piston skirt I thought too though right?

yes, well not always, depends on the design but the pin does need to move higher up in the piston though

And a longer rod may require more cam clearance etc I think too.

Ah engines, fun stuff. Much better than math.

Clearances for the block skirt, wrist pin, PTV, and everything else exist in every motor. Doesn't matter what you wanna put in it, a proper build will check it and do machine work as needed.

Agreed, but with longer rods or bigger rods you face more area to trim away. And I think you have to run a small base circle cam in some cases right?

(BTW you didn't have to delete those posts, appreciate it though)

It all depends on the math and the clearances. There is no automatic do this and you have to do this. Some brands have bigger or smaller castings and the way some cams are cut they just naturally offer more room.

You need to have to start picking the actual parts to be used before you can plan to do any of that kind of machine work or spend extra time/money looking at a different cam.

Yea, I know, I just like speculating and trying to learn these things.