Engine swap question

I have a 2004 Murray 40" cut mower (405000x8E model) i'm doing a engine swap on and had a question about compatibility

The engine i'm Replacing is a 13.5 hp briggs I/C Model: 21B807 Type: 0239E1 Code 040913ZA
The new engine is a 17.5 hp Briggs Powerbuilt Model: 31C707 Type:3346G1 Code: 100923D

Edit: new motor is from a poulan 42" cut model po17542lt