I have just finished building a new ZL1 engine with the 12370850 Chevy block. I am having an issue with the distributor (MSD 8360) not going deep enough into the block to reach the standard length oil pump driveshaft. I am using a Moroso 22080 driveshaft. The other reason I suspect the distributor is not going deep enough is that I measured the distance from the distributor mounting face on the intake manifold (Edelbrock 7561 Performer RPM Air Gap) to the oil passage in the block (where oil needs to go past the distributor shaft - see the image below) and it is at a lower level than the area on the shaft that should line up with the passage.The area on the distributor shaft where the oil needs to bypass the shaft is 5" from the mounting flange but it looks like the oil passage in the block is more like 5.25" to 5.375" (it's hard to measure exactly) from the manifold mounting face.

The distributor is all the way down on the manifold and it is still not reaching deep enough into the block. I could use a longer driveshaft but that doesn't fix the oil passage problem.

Has anyone else ever come across this problem? I primed the oil pump with the drill attachment tool prior to installing the distributor and was getting around 70psi on the gauge. After installing the distributor and firing the engine for the first time I had 0psi on the gauge! Ouch! That's when I started taking measurements and discovered this issue.

 

MSD does have a distributor with an adjustable collar to tweak housing height in block available.

 

Thanks Kevova. I have seen the distributor but it does not have vacuum advance and requires an external MSD box instead of being a ready-to-run distributor. I just disassembled mine and am having a friend machine off the mounting collar. I will use the MSD 8539 adjustable slip collar so I can use my existing distributor.

I still have no idea why it should be off as far as it is. All the parts are for a standard (non tall deck) engine. Oh well it's time to move on and take careful measurements to set the adjustable collar.

 

Put bearing Blue on your oil pump primer tool and it will leave a witness mark on tool,measure from base where it sat on manifold and how far down the blue has been wiped off, Usually this problem is caused by the cyl heads and inlet manifold height.There is normally plenty of room for the O rings to seal. Measuer from manifold dist face to oil pump,(top of tang on pump and then compare measurments and I think you will find your oil pump shaft is to short,also put some Bearing Blue in the dist gear to se how far the shaft is going into gear. There are several shafts avaliable in different lenghts.