SR20 Nismo main/conrod bearings direct fitment?

Hey gents, I'm currently buying parts for my sr20 mid power build. I can't decide between using oem nissan or nismo big end/main bearings. Are the nismo bearings a direct replacement?

My sr20 block has 2 oil ports on the block that line up with the oem bearing shell. 1 of the holes is quite small which I'm assuming is to help create an oil wedge.

The nismo bearing has 5 oil holes. What are the extra holes for? Are these to create an oil pool?

Are the nismo bearings like gtir bearings where you have to machine a groove into the block for an oil passage?

Any feedback on nismo bearings would be appreciated.

The crankshaft journals are all in good condition and match the oem graded specs.

Pictures of oem nissan bearing/block and nismo bearing

I believe NIMO is owned by NISSAN, in much the same way AMD is owned by Mercedes, HSV by Holden, etc.

It is possible there are several different drillings for different applications that use the same shell dimensions, with only the block drillings being different. For example (I'm not familiar with the engine) it appears there is a drilling on your engine for the chain tensioner/oil spray, other engines may have drillings for oil squirters/jets, or have different locations for the oil galleries and so be drilled differently.

It shouldn't be a problem as the block side is relatively unloaded and the unused holes should be blocked by the block.

However. it seems that the half that goes in the main bearing cap is also grooved, personally I would use a non-grooved bearing there because it will have a much higher load capacity, but that may just be me.

ACL Bearings have different upper and lower shell where the lower shells have only small tapered groove in the corners. I always use them and always had great results. Also used OEM ones without issues for stock engine refresh.

As for machining a groove for oil passage, never had to do that in a RWD SR20.