I have a 96 which is suppose to come with PM rods. Well I've heard 95 and lower don't but I installed a new motor and I'm not sure what year it come from. Would these rods have certain markings or a # on them or a different shape? Let me know because I need to see if I have them for my rebuild because I'm thinking about using the PM rods again because the motor isn't too old.

 

The powdered metal connecting rods were phased in during '94. All '95+ will have the PM rods.

 

my pm rod caps are rounded with no balance pad, at least it's not like the older gm rods
if you have them you'll know
it may have better rods , they look like the older gm rods also, it would be best if you can find who put the engine together and ask them

 

A PM rod is smooth with no coarseness like a forged rod on the surface and are a weird color gray.

 

Well here's the deal, the one motor I have has these rods that are rounded at the cap and they both look the same but one I have has GMA 312 on the rod near the bolt and is rounded with a flat side at the rod bolt. The motor in my car has rounded caps but at one side of the rod bolt it is flat with a dot on each half I guess to line them up right, no numbers or nothing, may be a 5140 and it's kinda greyish at the top. so what do I have???

 

Any pics?? POST PLEASE also this motor is a factory block, which means it was ordered brand new and has kb 4.060 pistons and the rods im not sure if they are a 5140 or a pm rod but i know in my stock 96 motor I bent one of my pm rods.

 

If they are SMOOTH they are PM,I mean smooth like a table top and not the sandy grain of a forged rod.

 

I'll post pics of them but they are smooth right but you can see little spaces in the metal I guess like from the mold, kinda like pores.

 

This is a picture from the "Rebuilding the LT1" article:

 

so the right one is PM350