RB and Max Wedge rod pictorial reference

[Lefty71]

Because Bill76 asked about numbers for the heavy RB rods ( and because I have all these on hand at the moment ) I figured I would throw together a pictorial reference of the four different RB connecting rods I have seen come from the factory. From left to right; a typical LY rod; casting #1851535, used in pretty much everything at one time or another. This one is actually an unused Direct Connection piece from a very closely matched set. Next in the line up is the early Maxie rod #2406395 which is listed in the "special parts list" for max wedge cars by Mother Mopar. I do believe these were also used in the 413 equipped Chrysler 300 letter cars. If anyone has details about additional applications for these rods, please shout out. At some point the need arose to make them even heavier (Stage III?) and they came out with #2406886. Finally, for reference I've got the 1970+ six-pack rod #2951908 which was also used in many heavy truck motor applications. The trend here obviously more beef in the beam area and a little tougher around the pins as well. The question I have is, are there others?? HTH, Lefty71

 

[BeepBeepRR]

This should be a sticky... Very good reference material.

 

[PRHeads]

If someone has an old DC or MP catalog from when those rods were current, maybe they could confirm I’m remembering this correctly......

There were some DC/MP rods that where forged using the std LY dies, but we’re made out of better material.

As I also recall........ they were big $$$$.

 

[oldbee]

If someone has an old DC or MP catalog from when those rods were current, maybe they could confirm I’m remembering this correctly......

There were some DC/MP rods that where forged using the std LY dies, but we’re made out of better material.

As I also recall........ they were big $$$$.

Definitely a bell ringing in my head. High nickel content? Early 70’s?

 

[Lefty71]

There were some DC/MP rods that where forged using the std LY dies, but we’re made out of better material.

As I also recall........ they were big $$$$.

The LY rod I have shown is reported to be the same treatment the '69 six pack 440 cars received, which was Day-Glo tested or magnafluxed. Also the entire set is very, very closely matched, almost like they are blueprinted. I don't remember them being a special material, but there is much I don't know.

 

[PRHeads]

Found this...... claims 4340 material......

 

[Lefty71]

Took a little trip around the 'net looking at those numbers. The P5249888 is the only one I could still come across any info. There's a guy on Ebay with a set, he's asking $103 per each rod, has all 8, and his have the Mopar word forged into the beam, which mine do not. Found nothing on all the others.

https://www.ebay.com/itm/Mopar-Perf...Rod-/172324920933?vxp=mtr&hash=item281f5d9e65

 

[TrackPack]

I have a set of the Mopar performance P5249889 rods. 5140 steel I had thought?

 

[Lefty71]

I have a set of the Mopar performance P5249889 rods. 5140 steel I had thought?

Seems they would be 4340 as @PRHeads has shown above. To muddy the waters further; last night I found in my old (1992 vintage) Mopar Engines Speed secrets book, AKA the Larry Shepard Bible, that Mopar was also selling at that time part # P4349793 which is also an LY rod but it is made from 8640 forged steel, double shot peened and magnafluxed, and also includes higher strength nuts/bolts. The advantage being higher strength, while keeping the weight very close to stock.

@miller just posted a snippet in this thread
https://www.forbbodiesonly.com/moparforum/threads/max-wedge-rods.175067/
which has a small footnote mentioning the '69 440-6 rods which are 100% Magna-glo inspected, yet no mention of them being a special material. This is what I had thought my DC LY rod set was, cuz I don't have any paperwork at all with them. BTW, anyone know what exactly the original materials used for rod forgings would or could be??

 

[PRHeads]

I was pretty sure the rods I used in some SB oval track motors were 8640 and not 4340.
They had the same forging number as the std 360 rods, but they were a different color......more of a light grey.
This would have been around 1990-92.

The catalog info I posted above came from a 2001 catalog.

 

[TrackPack]

Turns out that they are 4340 steel as you posted.

Found this in a 2002 Mopar Performance catalog:

 

[PRHeads]

It appears the earlier rods were 8640, and at some point they started offering some made from 4340.

 

[wyrmrider]

There were also some "nascar" rods which have larger bolts and are beautiful pieces
I have one somewhere but I've moved and might take awhile to find it
the high strength bolts are SPS just as good as anything else and less money than ARP
They used to be one hell of a value through Direct Connection- Like $32 a set

 

[Cranky]

It appears the earlier rods were 8640, and at some point they started offering some made from 4340.

I remember the 8640's being offered....mid 70's or so?

There were also some "nascar" rods which have larger bolts and are beautiful pieces
I have one somewhere but I've moved and might take awhile to find it
the high strength bolts are SPS just as good as anything else and less money than ARP
They used to be one hell of a value through Direct Connection- Like $32 a set

Thought the NASCAR rods were Hemi rods?

And the problem with the heftier rods in the wedge engines were mainly them using the same size rod bolts. Weak link.

 

[Lefty71]

I have one somewhere but I've moved and might take awhile to find it

NASCAR rods!

If you stumble across, this is the place to post a pic, thx. I always thought those were HEMI length too???

 

[wyrmrider]

There were some longer than hemi length but not the massive things hemi rods are (and not shaped like 6 pack more like super LY)
heat treated, polished the whole 9 yards
did have larger bolts
been 10 years since I looked at them- there were several varieties

 

[Lefty71]

Here are some weights for example of the rods (or similar to) pictured above; these are all unmolested examples, with cap, bols and nuts, NO bearing shells.

LY-..................... 832 grams
Early Stage rod..... 845 grams
Late Stage (III?)... 907 grams
Six Pack rod......... 929 grams

I think the only real surprise here, in my mind anyway is just how heavy the late Stage Maxie rods are, while being visually very, very similar to the lightweight LY unit.

Lefty71

 

[Old Sparky]

I have a 440 six pack motor that is marked as special pistons and rods.
It has LY rods, forged crank, and was built Dec 70. As I understand it the 6 pack engine LY rods were forged, peened and magnafluxed.......seems I read somewhere that they were different material as well.