Topic: 16 or 18 horse heads

[Briggsman]

How do I know if I have 16 or 18 horse heads.  Are there any numbers on the heads that indicate what I have. These are heads for a horizontal motor.

[Michaelgc7]

if you can CC the heads the 16hp have 20cc combustion chamber and the 18hp has 30cc combustion chamber, also it is often engraved 30 or 35 inside the heads beside the rocker arms, 30= 16hp 35=18hp

[Briggsman]

Yes thanks. I have three sets. One says 30 the other is 35 and the third set is blank.  But putting a 16 horse gasket around the combustion chamber tells me it is a 35 cube or 20 horse head. Thanks for the info.

[rotten ron]

The 23 hp heads have higher intake and exhaust ports,it is easy to see as the ports are nearer to the valve cover,the newer head flow lots more than the ones with the lower ports

[Briggsman]

It's my understanding that the 23 heads will work on the 16 motor. But having said that if they do work I'm guessing you're going to lose compression as the 23 heads have a bigger chamber. Is this correct?

[Cheen1989]

Also the intake ports on 23 heads are a different shape.