Never did one in a pilot house but yes normally you can. Remove the trans mount lags you then can use a bottle jack with some blocks under the exhaust manifold and pivot the engine forward on it's mounts to lift the back a little. Or you can get some pads for the gunnel's and put a couple of 2x6's on end across and use a comealong to lift the rear. Keep in mind a trans like that weighs around #100. Here is a picture of my Vdrive's trans coming out, you can see the bottle jack in place
I haven't worked on a PH20. That bulkhead seems odd. Doesn't seem to do anything. A call to Richard Shepard might be valuable. Should be able to find his contact info with a search of the site. He worked for Shamrock back then and has a wealth of info. He told me how (what to cut) to get the fuel tank out of my 17'.