I'm trying to figure out how to do a compression release on a dual plugged head. The lower plug is small/short reach. I want to be able to crank the engine with the ignition off against no compression, but there doesn't seem to be room in the head for another valve. So maybe some way to hold the existing valves open? On the other hand with the throttle closed there shouldn't be much air in there so maybe I'm worrying about nothing? Sort of like doing a compression test with the throttle closed.