440 HP(Six pack rods)

The 6bbl rods are heavier, and too heavy for the normal forged crank counterweights. So they use a balancer similar to the Hemis. It is unique. Brandon's close... the pistons in the later 440s with these rods are shorter and lighter, so they required less counterweight and therefore the factory used the std balancers. However, there are plenty of factory 6bbl engines that left the factory with std Magnum cam, rods, and pistons. Especially the early units with the aluminum intakes. If you have the rods and want to run them I'd suggest you have the shop balance the assembly. If you run light weight pistons they may be able to do it without Mallory. It's a crapshoot until your parts are spun and the bobweight is known.