Angle milling BB heads.

Just did a search on this subject but really didn't find any info. Any benefit or a waste of time and money?

to angle mill will ... change valve to piston angle . change the location of the valves relative to the bore center , unshrouding them. it changes cc's which will increase compression and more. all are tools which can be used in conceptual forms. most [true performance] modern heads of today have taken many of the "ideal changes" that angle milling achieved and designed them in to the production version. there is a lot to be gained by doing it if you are stuck with iron heads from a rule standpoint or other reason in my opinion. it can be expensive to do it correctly by correcting head bolt hole faces and intake angles etc.....I have even moved the dowel location to get the valves better centered !

It is a stock eliminator trick to get a more direct flow into the combustion chamber. By doing so, you change the rocker arm geometry. You may need to open up the pushrod passages in the head, shim the rocker shaft, etc. I'm just going through this with my 318/4V Aspen. Picked up 4HP.

This, with todays heads, not needed. Not even worth doing it original heads with todays options.