engine and drivetrain clatter from below

[vintage_car]

I've notice a bit of a clatter, and can only describe the sound as that. When going from one gear to the next if I shift maybe a bit to soon I hear a little clatter when the car lags b/c of the early shift, but goes away once I reach the appropriate RPM/Speed for the gear. I can't tell if it is coming from the rear end, exhaust, transmission, or engine? Anyone have suggestions?

[oh2fly]

Are you familiar with pinging? What rpms are you shifting at? Stock engine? Octane used? Timing set at what rpm? If running cheap gas now, try a tank of super and see if that helps. I try and not lug these motors. Keep the rpms between 2500 and 5000 and see if it is any better.

[eastsidebimmer]

check the fitment of your exhaust pipe over the rear subframe. Mine only has about 1/2 inch clearance and makes some strange growling noises at specific speeds.

Adjustment is possible, within reason--but its sort of limited to what the trans mounting bracket will let you do. Anyone have more advice?

Ben

[vintage_car]

running super already. more info...since there is construction on the interstate I travel I went on the road that had concrete on both sides so I could listen to the car. At normal travelling speeds I'm fine, when I increase the speed, no matter what gear I get this clatter, almost sounds like rocks rattling around in the exhaust pipe. It doesn't do it just sitting there and reving the engine, I have to be moving, so I don't think it is exhaust related. Coming from the middle or rear of the car, I think. I'm going to go tug on the driveshaft to make sure it isn't loose, check the motor mounts and see if I can see anything from the exhaust. It is a stock 121 with Dual 40DCOE webers and a header. So weird. Anybody else have suggestions on what to check.

[bimmertech]

i had a 320 in the shop once that did exactly the same thing. i found one of the hangers broken off of the exhaust. welded it back on and noise was gone