I am doing a stock rebuild on my 03 350z Track using all OEM Nissan parts(complete gasket set, main/rod bearings, oil pump, main, rod and head bolts).

Engine has been torn down for 3 weeks now and only thing holding me back on reassembly has been rod bolts. They came in this morning and the new OEM's are nothing like the ones I removed the rods that I ASSUME(d) are OEM because the previous own bought it new and claimed to have never done more than basic maintenance.

In the pictures below, the rod bolt on the left is the new OEM that I ordered from Nissan(called nissan to verify part numbers) and the one on the right is what was in the rods when I pulled them. As you can see, the new OEM is short threaded vs the full threaded that I pulled out. Could Nissan possibly have changed the design of the oem bolts? I have searched quite a bit and the only similar ones I've found online to what I've removed are "nismo reinforced con rod bolts." Any insight would be much appreciated.

 

The one on the left is the newer Rev-up motor rod bolt. The right is the older DE rod bolt. They say it can handle the 7200rpms much better. But anything past that is a real guess on the life expectancy is only that a guess.

 

Thank you very much for the response! Pleasant surprise to know I have stronger rod bolts now