crank balance

[justcruisin]

I'm sure this has been covered before but could someone tell me if I am doing the right thing. I am sending my rotating assembly off to be balanced. The crank is the original 70 440 magnum forged crank external balanced. I have ditched the 6 pack rods and cast pistons in favour of srp pistons and k1 rods. I have a neutral steel balancer, neutral flex plate and converter. From my calculations the bob weight of the new assembly will be considerably lighter at a little over 2400 grams. Will this balance up OK without the use of adding heavy metal? Also what is the difference between an external (6 pack) and internal forged crank besides the way in which they are balanced?  Thanks for any help.

[firefighter3931]

It should balance internally.....no problem ! The 6-pack rods weigh a lot more than a forged h-beam and the newer pistons will be way lighter than the factory slugs. It won't need any mallory added....if anything, some weight will need to be removed from the crank to balance the rotating assembly. 

To answer your questions on the crank....there is no difference between the internal/external balance forged cranks. The heavier rods required the external balance components.



Ron

[justcruisin]

Thanks Ron, didn't want to walk into the machine shop scratching my head.