This is a frequent question on the forums and short of looking for yourself through the inspection port, it was hard to know for sure because apparently some later engines had forged rods after the initial introduction of PMR. I found this recent message on the Hypermax site re:forged rods.
Moderators: Perhaps you can make this a sticky as it is a frequently asked question.Here is the engine serial number break down for the forged and powdered connecting rods. Check you engine serial number on the valve cover build sticker or you need to look at the block where the oil cooler is bolted to it .
Start of production thru 1425746 are Forged Rods
1425747 thru 1440712 are Powdered Rods
1446713 thru 1498318 are Forged Rods
1498319 thru final production run are all powdered
Or you can break them then you know what you have-Ha Ha-Just kidding
The reason for the break in serial numbers is a "test" run to be sure there were not any issues with the powdered rods. Once the process was production tested the powered rod process was used until the end of production.