The fuel pressure should be 58 psi, so that could be the problem if it is only 48 psi. Have a check that the spark plug screw caps are fully tight as they sometimes work loose and cause ignition issues. NGK Iridium DCPR7EIX are a good alternative to the standard Champion RA8HC spark plugs. There is an equivalent Harley Davidson ignition pack p/n 31655-99 that may be easier to obtain. The standard Morgan fit is S&S 55-1576. Magnecor do some very nice replacement KV85 ignition leads p/n 2547, if you find you do need some new leads.
Do the NGK Iridium plugs cause any interference with the ECU, either the MMC ecu, or the Emerald ECU?
