No worries, as we all know sometimes the very basic's evade us when were looking for a clue sorry i cant be of more use and sound less patronising, wish i were there looking at it

And you have had it running in the past...?

If yes then Hmmmm well if you've gone EFI flywheel then hopefully the CPS is aligned/spaced right so timing/signal should be all good..
as long as the sensor is..

id pull the feed off the pump be sure its getting a good strong flow up and not just spitting returning, might pay to check fuel filters past the fuel filter an all..then good strong spark next..are the injectors know good/clean?

Does sound like its fuel related, id be tempted to adjust the fuel pressure abit see if the cranking tone changes, should crank over nice and quick if fuels flowing, and or also check the TPS (Throttle position sensor's) all good an all.. then its back to checking every strand of wire and sensor followed by re-doing your level one motor vehicle maintanance NVQ again, check fuse first......

Fkin EFI


Good luck fella