Oil dip stick

[Ozzsp250]

I have just run into another issue on the replacement engine I'm tuning prior to installation in my car.
The dip stick on original engine is much longer than that on the replacement engine. The dip stick housing tube is also longer on original engine.
Original dip stick housing protrudes from engine block by 5.5", with the oil level single mark at 7.5" to oil level from lip on dipstick.
The replacement dip stick housing protrudes from engine block by 5.125", with the upper oil level mark at 8.625" from lip on dipstick. I have no idea what the markings D600L-3000 mean.
With the correct oil quantity neither dip stick appears correct however the long one is close.
Anybody had this issue or similar?

[A.N.Other]

Is the replacement engine the same as the original, SP/saloon ? Are the sumps the same type ? Are the oil pump assemblies the same ?
My experience of filling up during an oil change was to fill to a quarter inch below the mark. After a run and then cooling again the level would come up to the mark.
The SP will happily run with the level three eights to half an inch above or below the mark. But if the level is higher rather than lower it may help with cooling.
The top stick with the measure by it looks like the original SP type.

[tjt77]

The SP 250 has a shallower sump (oil pan) than the 2 1/2 litre sedan/saloon.. and also different (shorter) oil pump pick up.
On the saloon engines, the oil level on the dipstick equates to approx 4" deep of oil in the sump to be in the 'mid way' position on the dipstick .. this corresponds to Oil level approx 1/2" above the base of the oil pump body.
Given the SP sump is shallower, you probably need +/- 3 1/2" of oil in the sump to be at correct level.. Id think the critical factor is to be sure the oil pump body is immersed by 1/2" above its base plate. Unfortunately I dont have an SP sump or dipstick on hand to measure.. perhaps someone else has and will chime in here.