Something is making an annoying metal banging noise when I hit bumps in the road!.....It's fine driving on a nice smooth pavement.....The noise appears to be coming from the center rear, underneath of vehicle.....The car is a frame off and I tightened every nut and bolt under there including the spring shackles, u-bolts, shocks, gas tank, rear bumper, rear spoiler, body mount bolts, exhaust system, etc. This car is equipped with bolt on frame connectors and I notice that the floorboard is resting on the frame connectors, towards the rear.....Could it be possible that the frame connectors are hitting the floorboard when I hit a bump in the road?.....Is there supposed to be clearance between the connectors and the floorboard?

Are you sure the driveshaft is not hitting floorpan or muffler. I had a muffler hitting floorpan only on hard pumps in a 76 TA. Was hard to track down. The mufflers were tucked tight.

does the exhault come out between the leaf springs and rear quarter? i had the same problem and tracked it down to a loose shock tower bolt.
Jason

No, it doesn't sound or feel like a moving (driveshaft) banging noise, there's plenty of clearance between the shaft and floor/muffles.....I recently ridgidly mounted the mufflers to the body and it really appears that there is enough clearance between floor/muffles.....I might add, I'm not running any tails.

loose shock tower bolt.



All those bolts are tightened down too!.....The banging noise appears to be coming from underneath the car.....I'm not running any tails either.

If the floorpans were resting on the frame connectors, would this cause any banging problems when hitting bumps in the road?

If the floorpans were resting on the frame connectors, would this cause any banging problems when hitting bumps in the road?

Hmmmm....I dont think so. How long has it been doing this? what have you messed with on the car lately?

Remember, even tho you think the bolts are tight a bushing may be a hair to small or short and it will cause thump when hitting bumps in the road.
Does it make the same noise going slowly over the bumps? how bout 25 mph? how bout 60 mph? does noise increase with speed? is the noise coming from the front, middle or rear of the car? when you swerve it does it feel like something is loose? Pinion angle can change over hard bumps and under load and in some extreme cases shove the tailshaft against the floorpan. Maybe the transmount bushing not quite positioned correctly? I would recheck bushings on the top of the shock mounts in the rear of the car and make sure the bushing arent loose. the bolt may be tight but the bushing may be worn.
I know you stated complete nut and bolt resto also...:D
Good luck and let us know the outcome.