Blaz, where doyou get these numbers from
The horizontally opposed engines are all flat heads.
The book time is 2,5 hours .
and I am yet to do one in under 4 hours and that was after the shop was closed, phone turned off and flat out start to finish.
It is a really big job, both heads have to come off as does the carb o get at the valve chests.
There are 4 impossible to get at screws holding the cowel on on the operator side of the engine.
Then when you have finished there is retuning the engine