Motor Swap (LA360/408), Now Vibration

Johnny Mac said
That was fast!

Thats about 8 years old per the serial number.
Was ordered as just a longblock. no balancer installed. no intake, dist, carb, etc.
looking at the damper, it looks like a factory style to me. Magnums had serpentine pulleys...so best guess is it's an LA damper? or at least an LA intended damper? unless you can see a weight bolted on the back? but those look like factory ish balancing holes.

Also... this a dent maybe...? (RED BELOW)
View attachment 1716406075
i'm happy to sell you a damper at cost. best case, it fixes it, worst case...you have a new damper at a pretty good price, and the damper is scratched off the list of problems? could also use on the 340 with weight change (comes with them all)

But before you throw any parts at it, are you absolutely positive the exhaust isn't resting on a body seam, or headers touching the frame rail, or something coming in contact with something else?

have you ran it w/o the belt on it? (possibly an accessory with a bad bearing?) or crank pulley wobble?

We had a guy recently chasing a vibration, and when he put the car in gear, the engine flexed enough for the header collector to touch the starter motor (non mopar) would rattle the mirror out of focus.

I definitely like the idea of scratching the harmonic balancer off the list - That is the only thing not new attached to this motor. Maybe this worked for the previous owner in a automatic application where it does not work for me in a manual application.

These MOPAR's and their balancing.... man. I thought it was tough enough knowing I had the ONE YEAR of 340 External Balance... Add this one to the list now too.

Unfortunately I cannot really see the back of the balancer - I'll pull it off and get more photos.

I will also inspect the exhaust. I DID have to remove the passenger side pipe in order to install a O2 bung for the Sniper 2 I am running... MAYBE, just MAYBE it is interfering somewhere. Other than that, the drivers side, both manifolds (I know I know, should let this motor breath with headers - eventually) are what came off the 340 - which did not vibrate like this.

I'll remove the accessory drive belts, remove the dual v pully from the balancer (alternator/PS), and fire it up to see if the problem persists prior to removing the Harmonic balancer.

Thanks for the tips - I want to drive this thing!