Road Runner Nest

Guys,
I was wondering if anyone seen or have a cast crank 383? If in fact they do exist, what years? If the harmonic balancer is the same? Torque converter weighted? I know about forged being internally and cast being externally balanced. I've read so many forums and technical articles that all say something different.

I believe all big blocks had forged cranks up to 1970. After that it depends on the motor.

http://www.moparts.org/Tech/Archive/motor/36.html

The reason I'm asking is that I have a vibration when idling and when being revved up. The engine is a 70 two barrel and out of a coronet station wagon. All I did was install a mopar camshaft and a four barrel carb. I changed fan and water pump thinking that would help, but it didn't. Only thing that has me wondering is the torque converter. It's for an internally balanced(non weighted) engine. I might have to pull the oil pan off and look at the crank.

the cats crank was used starting in 71, on the 2 bbl motors only. In 72, the 400 was introduced, with the same cast crank, unless you had a 4 speed, those motors got forged cranks.

What's the harmonic balancer look like? Can you post a pic?

Well guys i pulled the pan and its a cast crank. I read numerous forums and other guys said they had also. If someone says they didnt use cast in 70, then they are full of it. I believe its still internally balanced since it has a normal harmonic balancer and the crank counter balancers are drilled.