Did 440 4bbl 375 horse motors get 6 pack rods?

I'm NOT questioning what other engines which the "6-Pack Rods" might have been installed in, BUT my question is about them being "bigger"? Was this "larger" situation in the beam, in the crankshaft end, or where ever? The reason I'm curious about these things, although I suspect there is a graphic in one of my old Direct Connection Race Manuals, but if they are bigger and allegedly stronger, would they also weigh more than the normal 440 rods? IF they are heavier, NONE of the FSMs I looked at today (downloaded from MyMopar.com) indicate such. Every 440 350/375/390 horsepower engine in the FSM states the rods weight 29.8 ounces/846 grams. No exceptions. I looked at specs from 1969 to 1973 model years.

I'm fully aware of the different part numbers, but I'm concerned with "WHAT" made them unique and justified their own part number? Especially if they are all the same weight (according to the FSM and AMA Specifications)!

Just some thoughts,
CBODY67
 
This is out of a D.C. Engines book from ‘84.
IMG_6602.jpeg
 
66 Monaco 500 365 said:
I've rebuilt a few HP 440s in my time, and only one, a 1972 Polara CHP 440 4 bbl had 6bbl rods.
I watched an old YouTube vid today from Nick's garage and he said that "most" '70 375 horsepower E body 4bbl 440s get 6bbl rods.
What is your experience with B or E body factory 440's?
Did 70 or 71 4bbls get 6bbl rods?
Thanks for the info!
Scott
Click to expand...
No it has "LY" Rods. But some of C-body in 1970 or 1971 more likely New Yorker has 6pack Carnk, Rods and harmonic Ballancer. That is truth lol
 
I used the regular “small” rods in my ‘66 300 440 when I built it in the ‘80s. I run a six-pak intake. The rotating assembly was custom-balanced and reliably pulls 6000 RPM.
 
My numbers matching 69 440 6bbl. Did NOT have 6bbl. rods. The two 70-72 highway patrol 440 builders I plucked from the junkyard both had six 6bbl rods. This was back in the early 80s so I would not know any specifics on the builder 440s past them being 70-72. I would not have pulled anything 73 or newer because in those days supply was plentiful, and I could always stick to the muscle era when Parts chasing.

Steve weim55 Colorado
 
Magnafluxed, Double shot peened and mildly polished rods with high strength bolts and nuts.
Using better forging material known as 8640. Staying the same weight as standard rods.
Part number P3690649.
According to the D.C. engines book.

That appears to be the difference between the rods.
The engine book also notes that these are better rods for racing.
 
cuda hunter said:
Magnafluxed, Double shot peened and mildly polished rods with high strength bolts and nuts.
Using better forging material known as 8640. Staying the same weight as standard rods.
Part number P3690649.
According to the D.C. engines book.

That appears to be the difference between the rods.
The engine book also notes that these are better rods for racing.
Click to expand...
That was the spec for the rod that Direct Connection/Mopar Perf sold and not necessarily what was in the 69 1/2 6bbl/six pack engines.

I don't know as anyone has found Chrysler's documentation on differences on some of the parts that were used and the conn rods seem to be one of those mysterious parts. What was believed by many was the 69 1/2 rods were hand selected and magnafluxed. You could assume that meant they were checked for balance and size, but that's assumption based on hearsay, so it's not worth much. I have never heard that they were a different alloy, although with lack of proof either way, it's possible. I think they would have pushed that in the advertising and hype if it were, but who knows. It is established that the part number was different that any other 4bbl rod and that is the only thing (so far) that is established.

It's been my experience, and this was pointed out by a couple of sharp parts guys, that a production line item would become a DC sold part with the addition of a "P" to the part number. That may not apply to all, but found it true on a number of parts.
 
Of course, one thing to remember too is that Direct Connection wasn't around in 1969. They did have a performance parts program, but IMHO, it got more serious about 1971(?) when they started the Hustle Stuff parts program. Dumb name... But it became DC in 1974(?).
 
Big_John said:
That was the spec for the rod that Direct Connection/Mopar Perf sold and not necessarily what was in the 69 1/2 6bbl/six pack engines.

I don't know as anyone has found Chrysler's documentation on differences on some of the parts that were used and the conn rods seem to be one of those mysterious parts. What was believed by many was the 69 1/2 rods were hand selected and magnafluxed. You could assume that meant they were checked for balance and size, but that's assumption based on hearsay, so it's not worth much. I have never heard that they were a different alloy, although with lack of proof either way, it's possible. I think they would have pushed that in the advertising and hype if it were, but who knows. It is established that the part number was different that any other 4bbl rod and that is the only thing (so far) that is established.

It's been my experience, and this was pointed out by a couple of sharp parts guys, that a production line item would become a DC sold part with the addition of a "P" to the part number. That may not apply to all, but found it true on a number of parts.
Click to expand...

Agree.

I think the DC reference in the manual is where the misinformation started and comes from regarding 'six pack rods'. That was years after the fact.

The Parts books and factory memos are contemporary to the discussion of what happened in '69 and '70's built cars.

It should be easy to find DOCUMENTATION, not IIRC, some guy told me or other anecdotal 'remembrances' along the way, supporting what was printed in the DC manual. There would be other FACTORY info supporting the position of the manual.
 
Last edited:
8721Coker said:
If I'm not mistaken the rods in the 413 industrial motor home engines are the heavy 6 pack rods. I have 2 of them boat anchor heavy engines with the thick heavy rods.
Click to expand...
All you need look at hamonic Balancer which you see little Houseshoe but not big one like Cast Crank that tells you has 6pack Crank and Rods period.
 
69CoronetRT said:
It should be easy to find DOCUMENTATION, not IIRC, some guy told me or other anecdotal 'remembrances' along the way, supporting what was printed in the DC manual. There would be other FACTORY info supporting the position of the manual.
Click to expand...
Exactly. In this Chrysler TSB, probably scanned by some guy drinking Bailey's, it spells the differences out.


wgDOlPp.jpg
 
Big_John said:
Exactly. In this Chrysler TSB, probably scanned by some guy drinking Bailey's, it spells the differences out.


View attachment 631814
Click to expand...

A contemporary factory document from 1969 regarding 'six pack rods'.

BTW...Baileys' just doesn't taste as good as it once did since I was honored with a 'custom blend'. ;) Thanks again.
 
Dutchrebuild said:
70-71 440hp engine got the heavy rods and special balancer. 72 and up to at least 75 440hp engine also got the heavy rods, but not the special balancer. I have taken apart many 70-75 non HP 440s that were in heavy duty applications that had the heavy rods, steel cranks, and windege trays, but no special balancer
Click to expand...
I've seen the same. The earliest of the 440-3 engines in at least in '73 had a steel crank, windage tray, 6 pak rods, and a double roller timing chain. Since the earlier high compression six pak rod engines had a very little external balance weight, the lower piston weight in the 8.2 c.r. -3 engines allowed them to be internal balanced.

Since the '73 440-3 was the cheaper motorhome engine that replaced the more expensive '72 413 industrial engine n motorhomes, the -3 got heads with extra cooling around the spark plugs, better quality valves, and exhaust valve rotators and were the castings used for Paul Rossi Street Fighter heads but he the later 452 casting based 440-3 heads typically IIRC.
 
72 440 HP's got the big rod engines too and forged crank, my 72 WSP has it. Lo pos got the cast crank.
 
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