The rods were subjected to a Zyglo inspection which is non destructive but more effective at detecting flaws (google it) The ones that failed the test were used in police, motor homes and other heavy duty applications well into the mid to late 70's. to my knowledge they all carried the same casting number so it is impossible to tell a true 6 pak rod from a failed but used in HD applications. Please correct me if I am wrong

I have a few of those failed ones

I believe the documents presented here refer to the 1969-1/2 released six pack stuff.

Unless I missed a publication some where I don’t think the inspected rods applied to the large beam rod released for 1970.

The 1969-1/2 rod released for the six pack cars were inspected and carried a blue paint swatch.
No swatch meant it was a plain old rod.

Agree but I would think they would have done the big rod the same process, these came from a motor home engine...rejects?

I have 1/2 of a failed one LOL I try to remember to take a pic of it

I have no proof but it’s my understanding they inspected the narrow beam because they were looking for premium rods for a reason, to prevent breakage in a likely severe environment. High engine speeds and harsh driving environments. We should use some common sense. A standard rod that is not defective lived in these cars.

I’m guessing the later rods didn’t need the inspection by virtue of the wider beam. I don’t recall ever hearing that street Hemi rods were mag’d or zylowed.
The NASCAR and drag race rods were and in some cases polished and shot peened rods we’re made available.

As for your rods I have seen many rods machined like this and don’t ever recall ever seeing a broken rod at the small end. Usually broken in the middle of the beam.

6bbl and ly rods almost always broke mid beam. Back in the 70s and 80s a compression check is how we saved motors, if the compression goes up 5lbs the rods are stretching and need changed. They are kind of like the sprag in the trans, any driveline failure you had better check the compresion, any increase change the rods. The crazy thing is the ly rods would last 50-100 passes after the compression increase, but eventually boom. On the 6bbl/ heavy duty rockers, at least the ones I have the metal is visibly thicker than standard ones.

I checked a known set of the DC rockers and come up with about .015-.020” thicker. At the side of the rocker.
I’m looking for my ball micrometer to check the pad and pushrod pockets next.

Is there any way that one could look at an A12 Six Pack connecting rod and tell if it is an original? Supposedly being "shot peened" does that take the sharp cast in characters and round the edges? This I know is an original untouched A12 Six Pack Super Bee engine (matching number to the A12 Bee) and here are photos of the connecting rod(s) and end caps. Any clues compared to a non-A12 engine?

Damn sorry that's the main caps duh I'll be back

Here's some pic's of a failed cop car rod. It let go during a burnout contest at an East coast Street rod event. My buddy won the contest and believe it or not drove the car home vibrating quite badly. The big end of the rod stayed on the crank. The motor actually survived with the valves being replaced, a piston, rod and new rings. Honed it and put it back together. It was in a 39 Desoto that was last known to be in Northwest. That motor took A LOT of abuse from two owners before it went north. The original owner was the one that lost the rod. I often wonder what happened to the car

Some interesting reading for some I hope. I'm sure a few here know this info first hand...

(Printed in 1966 for the 1967 HP and standard 440 cu. in. engines, does NOT include any info on the six barrel six pack engines, just developmental info to that point)

Mike

Neat!