Classic/Antique Car Repair: shakes bad, engine shake

Question
hi, I bought a 1976 dodge B100 VAN and had a shop put in a 360 rebuilt engine and took out a 318. thought everything was pretty much now new and even the bottom was done like tie rods,ball joints,springs,shocks,bearings and much more. then after all that work it went into the body shop. just got it back after 6 months gone and while driving it home on main streets the van was shaking so bad I couldn't see out of the side mirrors.even in part it shakes very bad.so I now don't think its the u joints because its shaking while in park. can you help??. thanks

Answer
Hello George,

A vehicle shaking this bad at idle only leads to one thing, engine. Did you run the engine before the truck went to the body shop?? Did it run well then??

Assuming the answer is yes, to both the preceding questions, I would next go to verifying the tune of the new engine: Inspect distributor cap, rotor, ignition wires and their firing order, distributor bearings and cam, points plus dwell and engine timing. The causes of your problem are so broad, that you need to verify the preceding in order to create a baseline to diagnose against.

And, you also mention that the truck spent an extended period of time in the body shop? Body shops can be notoriously dusty which may have gotten into the carb. Also, body shops don't normally care much about the tune of a car, jo so long it runs long enough to move in and out of the shop. Finally, it's very possible that some of the items  mentioned may have been jostled while the body repairs were being done. Partially removed parts may have been roughly returned to their original places and may be out of order firing order wise.

So, to make a long story short, get a shop manual and check the placement and order of all the preceding items. Then check for opens or shorts in the spark plug cables and finally, pull all the plugs and "read" them. Good cylinders have gray-white deposits on the firing end of the plug...anything black, dark or oily ends may be problems and point you into the right direction

And failing all of the above to find the cause,  check that the engine mounts are properly installed and are not cracked. Somewhere in the above, you'll find the cause of your idle roughness.

Best of luck,

Bob