There were a couple I can think of. One to remove the weatherstripping from the rear decklid (under back window). Rerouting the air intake hoses, and adding a stamped steel plate to the firewall exhaust manifold. This plate was supposed to prevent a fire if a rod made its way through the side of the block.
This never worked and is a guarenteed exhaust leak if it is done.
Thursday, October 16th, 2008 AT 8:43 AM