My '92 with the L98 has started leaking on the driver's side where the downpipe connects to the exhaust manifold. I took it apart to find that it is a ball and flange (no gaskets). New studs and careful alignment of the flange and it still leaked. I tried putting some exhaust sealing stuff on the joint before pushing it together, and it still leaks. Are there any tricks that I should know?

 

i got the same problem but its due to my y pipe being so old and dinged up the best way of sealing the donuts is to buy some high temp exhaust gaskets and make em fit nice so when u put the donut on the gasket will be sitting bettween the flat side and the manifold thus sealing it better.