If you spend time on your computer you can wade through all the engine parts being made in China and see that there are at least two companies making B heads.
https://www.alibaba.com/showroom/440-cylinder-heads.htmlThe Stealth head was developed by 440Source and it is not available from anyone else. The other heads have the slab ends. I believe the more expensive heads are what we know as Sidewinder heads or ProMaxx. The less expensive C. Haray heads are sold under many names and can be bought all the way from rough castings to finished and assembled.
These guys make everything! Cummins 6BT blocks, for example.
R.
