Briggs I/C vs. POWERBUILT

What are the differences in these engines aside from 1 hp, the powerbuilt is a new engine I pulled off a snapper, the other is my current 12 hp on the white race/rally mower
I was In the process of swapping these then I thought is it worth it.

Thanks in advance!

The I/C engine is “Industrial and Commercial” and is supposed to have a cast iron sleeve and possibly better internal bearings. I just read that in a few places. Guessing that the other one has an aluminum bore (no liner). 
Let’s see what those that really know, know.

That air filter cover is off the 13hp so I guess it has cast iron sleeve as well, where can I find the definite differences, should I just rock the 12hp

There should be several numbers somewhere on the engine... serial number and model number should give you the specifics of each engine. On the OHV engines, it is stamped on the head (rocker cover). Like this:

Aside from the sleeve and rod bearing differences, the two are basically the same. The 1 hp difference you won’t notice unless the 12 is tired. I say use the I/C because of Nevadablue’s point but there really is no major difference.