I posted this on FEBO, but there is not much participation there, so I decided to post it here as well. After all, a small block is a small block, regardless of what it is in.
I have a 73 Challenger. Originally a 340 4-speed car. Original motor blew up and was replaced in 74 with a factory 360 replacement motor. The motor is stamped a 74, and has no serial numbers, so this seems to support the story. I did not buy the car from the original owner, so I am not certain, but I am assuming that since it was a factory replacement motor, the replacement was done by a Chrysler facility under warranty circumstances.
Anyways, I have had the car for a few years, and really dont get to drive it much. I have always noticed that when I start to get on it, it has a vibration that shouldnt be there. It's a very high frequency vibration that makes the console and shifter buzz. Gets worse the faster you go, but I am positive its not a wheel/tire thing. I am pretty sure it is a drive train issue. There is no noise associated with the vibration, other than the noise that comes from the shifter, console, dash, etc. I revved the motor while in neutral, and it still seems to be there, just not as bad, so I am leaning toward an engine imbalance issue of some type.
I decided that this year, I am going to look into it, so I am looking for suggestions. Does anyone know what happened in a warranty motor replacement situation back then? Did they replace the whole motor, or just the short block? Could they have used parts from the original 340, like the damper, flex plate, etc, that may be causing the vibration? I know that some 340 parts are not compatible with the 360, and that a 360 was externally balanced while a 340 was internally balanced.
Any suggestions on what to look for would be really appreciated. I'd like to get some ideas and things to try before I start tearing things apart.
