Since the fuel pump button valves are a type of reed valve, they will "honk" if you blow through them. Your fuel line is not too long to cause problems HOWEVER, in addition to replacing the fuel pump diaphragm as a maintenance item, you should also check all fuel lines and fittings clear back to the tank pick-up to check for partial clogging.
The distributor rotor is one piece, epoxy glued to the shaft. It is not serviceable. The whole shaft/cam/rotor assembly must be replaced--that is, unless you are lucky and good. Find a good rotor and are able to free the glue off yours etc. WAY too much trouble.
I have in the past seen a set of new plugs refuse to fire at all yet when old ones were installed, the engine started and ran well--go figure. I have no explanation.
In the driveway, under no load conditions, all but the sickest of engines will exceed 5500 RPM. I have done this with engines with only two cylinders out of four running This shows nothing other than the engine is getting spark. It takes so little fuel to achieve a no-load high RPM that the engine will never starve in the driveway and I never recommend doing this. It is rough on the engine..
The 17pitch prop will allow the engine to achieve about 400 RPM more. HOWEVER: do not be surprised if speed does not increase and in fact may decrease. The lower unit, midleg, and prop you have is so inefficient that the engine most likely will never see 50--at any rate, it would surprise me. I though 43 was decent for what you have.
NOW: I don't remember the lower unit ratio on your specific engine, BUT-- if it is a 1.76 to 1 and if you can find an old 90 with a 2 to 1 ratio, using the 2 to 1 lower unit on your engine will gain at least 3 and possibly as much as 8 MPH. (turning a high pitched prop at slower rpm while the engine revs up higher has a lot less parasitic drag and frees more horsepower to actually move the boat) I have covered a lot of this stuff in past posts on the Force/Chrysler forum. Search my post there and you can read them.
By the way: You can cut off a 5/16 stainless bolt and use the unthreaded portion as a prop thrust pin. You can also use a 5/16 allen head bolt with a nylock nut on the end. That way, even though you can't use the tailcone, you will never lose the thrust pin and prop.
Oh, yeah---Do not attempt to use an electric fuel pump. They are not rated for marine use and are dangerous because they will not automatically shut off if the engine stalls. Simply a bad idea especially when the impulse pumps have proven reliable and mostly trouble free.