Head swap

Remember Commando valves are a different length to those in the Atlas, so pushrods would need to be Commando as well.

The rocker feed is in a different position, too... so that would need sorting. Been a while since I sold My P11, but Iwould investigate the head steady mounting arrangements for both as well....

Must ask if this is for performance increase? Will admit I found the stock Atlas lump more than adequate, reasonably smooth(!) and an easy starter. The riding position does more to dictate the top speed with these rather than horsepower.. IMHO

Previously jerry_welch wrote:

Is it feasible to use a Combat head on an Atlas engined P11?

I was looking at a Combat a couple of months ago and I noticed that the bottom fin on the head was almost touching the top fin on the barrel. I don't know where they removed the metal to achieve that (I assume it came from the factory that way). I would check how close the valves got to the piston just in case.