Briggs 14.5 HP fix or replace? Bolt patterns?

My Briggs engine seized, totally my fault, it is on DR field and brush mower.  I ran it at a severe angle for too long and I am guessing it got starved of oil and then it seized.  The engine is 14.5 HP, Model 31R677, type 0017.G1.  I am going to tear it down and go from there, I am not sure if it is rebuildable.
 
My main question is what engine would bolt in place?  Is there a range of HP that has the same crankcase and bolt pattern?  I am also not sure about the size of the shaft either.  Are all 14.5 HP the same shaft?  I found many 14.5 HP Briggs on market place and CL but I don't know if they will fit.  
 
As you can tell I am not very knowledgable with the specifics of these engines.  
 
Thank You 
Zeek