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

Almost all engines (around that size) have the same bolt pattern.  
 
The crank will likely be the same but measure yours against what engine 
your looking at....  
 
Pull the head and see how scored up the cylinder is...  IF it's still
not scored, you may be able to lube everything real good and re-assemble.
 
Also check for any slop in the connecting rod...
 
.