440-6 rods

[r15303]

I need to get a set of 440-6 rods for my 70 Chally.  Which is correct - 2951906 or 2951908?  Didn't know there were different ones.
Thanks

[Moparal]

908 is the big rod #.906 is the hp or ly reg rod#.  You buying new or used?  I got some good used ones, but I have to press the pistons off them

[r15303]

Alan - I'll e mail you

[matt63]

Unless your going for absolute correctness on a real 6 pack engine, the 6 pack rods may not be the best choice.  They are heavy and this puts added stress on the bearings.  I'm sure there are others on this board who can elaborate on this. 

[r15303]

Thanks Matt - I'll consider that.  I do want the correct dampener on the crank though.  I'm not as concerned about "correctness"  I have a set of LY rods but can't use a correct dampener with them unless I use alot of mallory metal.  Not sure which way to go.

[vinb]

Like Matt said , those rods are very heavy and who's going to drop the pan down and look.. You can get a set of rods from Manley Performance, if you want a good rod that doesn't weigh that much. By the time your machine guy get's done with your stock rods the cost would proably be better with the Manley's and it will be alot stronger...

[Chryco Psycho]

the 6 pack rods are not really any stronger than the LY rod , their extra weigth hurts their own strength ,But I had them in the 440 I built & I raced it shifting at 7200 RPM for 10 years with no problems either

[Moparal]

  with chryco. They can keep the tq up but will actually cause you to run slower times in some cases do to the mass recipricating weight. It takes longer to rev it up.  Seems to me that if you have the balancer for the 908 rods and the crank for the 908 rods, and depending on the pistons, you should be removing metal and not adding to it with the ly rods

Seem right to say chryco?

[Chryco Psycho]

the added rotating mass will slow down how quickly the engine will rev but conversly it can help the car launch with the extra inertia
 basically adding weight is not productive , lighter rotating mass is better

[v8440]

I wanna clarify a couple of things:  Added rotating weight will slow down how fast the engine revs.  Added reciprocating weight will just cost some power and is harder on the whole bottom end, including the block.  There is no inertial advantage to heavy reciprocating weight, like you might use a heavy flywheel for.  I'm probably not saying this correctly, but the reciprocating weight is not a constant force that you can tap like a heavy rotating flywheel/crank assembly is.  Reciprocating weight by definition is going back and forth, stopping at each end. 

If you want to use your correct 6 pack rod balancer, my advice is to just use the 6 pack rods and be done with it. 

[moper]

I wanna clarify a couple of things:  Added rotating weight will slow down how fast the engine revs.  Added reciprocating weight will just cost some power and is harder on the whole bottom end, including the block.  There is no inertial advantage to heavy reciprocating weight, like you might use a heavy flywheel for.  I'm probably not saying this correctly, but the reciprocating weight is not a constant force that you can tap like a heavy rotating flywheel/crank assembly is.  Reciprocating weight by definition is going back and forth, stopping at each end. 

If you want to use your correct 6 pack rod balancer, my advice is to just use the 6 pack rods and be done with it. 

   'specially with that last sentence.