I have a 1982 300sd, just replace the header pipe with a new bosal pipe. It seem that after the replacement the pipe hangs too low. Is there any way to adjust the pipe where it is a little closer to the heat sheild. Or do anybody know how low should the exhaust hang from the ground

The downpipe is bolted rigidly to the exhaust manifold and also bolted to the resonator section, therefore, you get the height of the two ends. There is no adjustment.

If the bolted flange is too low, check the rubber hangers that hold the resonators.