Morris Minor Owners Club

I am in the process of rebuilding a 1275 A+ engine. I recently bought a Minisport CA2 "fast road" camshaft and high pressure oil pump with slot drive. On putting things back together the engine will turm over by hand with the front of the camshaft flush with the front of the block but when I fit the oil pump the camshaft is pushed forwards so that the front shoulder of the camshaft is about 6mm proud of the front face of the block and this prevents the engine being able to be turned over as the crankshaft fouls the cam.
Should the end of the camshaft be flush with the block without the front plate on ?
Are all camshafts the same length?
Previous cam in the engine was spider drive, could the change to slot drive make this difference?
Is something wrong with crankshaft position?
Help
Dave

Hopefully these photos show the problem

Top photo shows when oil pump fitted and crabkshaft wont turn

bottom photo shows cam in position when oil pump not fitted and engine turns by hand easily

Flush with the face WHEN THE FRONT PLATE IS ON is correct (well 3 or 4 thou end float!) - but the cam must be timed correctly when you turn the crank - fit the plate, line the dots up and put the chain on - it will be ok.