340 = 318 harmonic balancer

[Plum Crazy Chris]

I have a 70 340 with a forged steel crank, and my balancer is shot. Will a late 70s ('78-'84) 318 balancer work for my application?

My engine is in the shop, and can't get it balanced til I get a new balancer, which of course needs to be ordered. I just love delays.

thanks guys

[rumblefish360]

PC Chris;

Yes , it should work fine. It is also a internally balanced engine. There should be NO problems.

[Hammer 74]

The 340 and 318 dampeners are interchangeable except for a 73 340 which is a cast crank. The only other difference is the crank pulley. some later model cars had equal spaced bolt pattern and older ones had 1 offset bolt.

[66Dart_GT]

? I was under the impression that the 340 is externally balanced, and the 318 is internally balanced! Did this change with the years? If it didn't change then it won't work.

JN

[rumblefish360]

66dart_GT;

1973 is the only year the 340 came as an externally balanced engine. It is an oddball balance as well. You cannot use the 360 stuff on it.

[shannon]

If its a balance from a 340 forged crank engine it will work, if its from a cast crank 340 it will not work. The cast crank balance has more material on one side of the balance than the other(like a 360 balance). Cast crank 340's were produced in 72 and 73.

[Darn Dart]

Must have been the late 72 340's that had the cast cranks, cause I have a '72 Demon 340 4-speed (7-71 build date) that came with a steel crank.