Tore into the 500's this past weekend and saw something that I wasn't sure about. I know the 500EFI's come with "H" beam rods and I assumed the carbed 500s came with the same. Did the older (99 model) carbed 500s come with "I" beam rods?

Is there any amrkings on yours?? Looking for letters, numbers or combo of both.

500 hp's all had gm forged rod's, the only ones that have I beam rod's were the 500 bulldogs.

Long block of a 500hp is no different than the 502 mpi's other than camshaft

500EFI's went to the Manley rods in there second year or so of production.

That's what I was wondering - if there was a change to the bottom end in the later years. So early efi motors and their carbed predecessors both used the GM rods, correct?

Correct. If you search the 500EFI on www.mercruiserparts.com you will see the serial numbers for when they switched.

Cool, 'preciate cha Griff. That's what I needed to know. I knew the later EFIs I saw torn down had the Manleys so it concerned me when I saw the GMs.