Cylinder head question

[Wilco]

I noticed a new head listed for sale as a HD head.

What cylinder heads were used on 151's?

What were the diferences?

[Fil Bonica]

There were three iterations of 151 series heads.
The first two had weakness in the area of the exhaust bosses.
Typically these heads did not use gasket to aid in sealing onlyutilizing grease
Bolts would seize and break off. The end of the boss had a tendency to fracture contributing to exhaust leak
The last style was the heavy duty version with much heavier bosses.
Also the valve openings were equipped with hardened seats for use with unleaded gas
The dimensions were altered for use of gaskets between intake and exhaust seats thereby elimnating many leak issues.
As it turns out the HD version is the only style. I am accustomed to working with.
Been spoiled over the years because I was able to find replacement units when. I was working on an engine
Hope that helps.

Fil Bonica

[rickf]

Fil, Do you still have any of those heads?