Head Replacement Mistake Kohler K161

[dixiebonsai]

Hello,
I have a Garden Way Tiller with a reliable Kohler K161 7hp engine on it.I truly enjoy tinkering with and using it.Unfortunately the spark plug threads recently gave it up.I bought a used head off of eBay that was advertised as a K161 head.When it arrived I noticed that although it looks identical from a distance and bolts on the same, that the combustion chamber in the head is shaped slightly different than my original and the footprint left by the the piston on my replcement head is larger than my K161 piston.I am now convinced I have a K181 head. Upon more research, I have discovered that the K181 runs at slightly higher compression of 6.8/1 vs 6.2/1 for the K161. The valves have clearance and it bolts up perfectly.Will I hurt my K161 by trying to run this head?

 

[Midniteoyl]

I am pretty sure they are the same head, with the difference being the size of the bore (bigger on the 181) making up the difference in compression ratios. If you measured and checked for clearances and all's good, slap it on and run it.

 

[dixiebonsai]

I appreciate the advice sir, I think you are right.I found yesterday this quote from a Kohler pulling tractor website, located here http://gardentractorpullingtips.com/cylhead.htm "The cylinder head used on Kohler engine model models K141 (6¼hp), K160 (6.6hp), K161 (7hp) and K181/M8 (8hp) was introduced in 1952, and are all identical. There is no difference. These heads shouldn't be milled because the valves are already close to the head when the valves are at full lift. All that can be done is resurface it on a wide flat sanding belt or large diameter disc sander to remove warpage and restore flatness, and to prevent a blown or leaking head gasket. OEM Kohler part # 41 755 25-S." The heads I have are milled out slightly different inside but I think it will be OK.