different conneting rods

[blazin_blazer]

my buddy works at a shop where they just pulled a iirc...a zz4 crate motor apart, installed h-beam rods,w/ new pistons, a zz4 ''hot cam'', and they had these left over. my buddy talked his boss into letting him have them and he gave them to me. he said w/ arp studs installed that these would be stronger than any of the stock rods i have. he pressed the pistons off b/c i'm planning on 11:1 pistons, but i'm curious are these rods as good as they make them out to be and will they even fit on older cranks and in older blocks??

heres what all my rods look like, weights on big and small end:

heres the pm rods he got for me:

the old rod parting line

the new rod parting line

the old rod small end w/ weight

new rod small end ...no weight

the new''pm'' rods look beefier everywhere except the thin cap on the big end...the beams themselves look really strong! smooth, where my older rods, look and feel grainy!

heres a link to some more pics,
http://s263.photobucket.com/albums/ii128/chevy_doctor/connecting rods/

you can see differenceses in the rods, but are they all they claim them to be? they recommended that i balance the rotating assembly, after haveing new pistons pressed on....and after i press new arp studs in the big end have it checked for out of roundness b/c pressing in new bolts can make them out of round,duh! ....

is this a good set of high quality rods from gm? will they be worthy of using, after new studs are installed and they are checked out? the engine won't be wrapping up into the stratosphere, but will be balanced! so anyone recognize these rods? what are they exactly? i've been told they are the best rods gm has ever made,(that they are powdered metal rods out of a stock ...iirc, zz4 ....is this true about best rods gm ever made?and again are they usable in older blocks on older cranks?

 

[4X4HIGH]

Those are the powdered metal rods (PM). Those are a very strong rod. The downside to those rods is they cannot really be resized if there is a signifcant failure. Those rods are sometimes refered to as a "crack rod". If you take the cap off you'll find that the parting line of the cap and rod are jagged. You cannot clip the rod or cap to resize that type of rod, they can be resized however but it will now require a larger OD bearing as the housing bore of the rod will need to be made larger since they can't be clipped. IIRC you can only get the bearings in a .001" and .002" overside on the OD.

I would not install different rod bolts since anytime a new rod bolt is used the rods "should be" resized and from what i just explained that should be avoided if at all possible.

Yes they can be used in any large journal engine except for the 400 since those use a short rod length.