I recently decided to upgrade my Colnago HP Dream with a new set of cranks and a new bottom bracket. I purchased a second hand Truvia Ruleur GPX Carbon crankset and GPX bottom bracket with external cups. When I mounted the cups the axle of the crank does not reach as far as it should. The shoulder on the shaft should butt up against the inside of the bearing on the non powered side (left) but this isn't the case so when I tighten the left had crank it pulls the chainrings up against the cup on the power side.

My question is, does anybody know of any bottom bracket shells with Italian thread at 73mm instead of 70mm, particularly Colnago. Does anybody know of a way to resolve this or am doomed not to use external bearing cups?

Thanks in advance,