I am working on stopping fumes from coming inside my '73 240Z. I am replacing the hatch rubber seals, both upper and lower. I have a question about my tail pipe. The end of the tail pipe is 3 1/4 inches from the end of the rear bumper. If I extend the tail pipe to the end of the bumper, will this help with the fumes problem as well? Thanks.

It seemed to work in my case. I also replaced the tail light gaskets which seems to be a must. Do a search on the site for "exhaust fumes". Plently more info! PM me and I'll send you a word document about this stuff if you want.

Yes, tail light gaskets, hatch seals and check the holes where the gas tank vent hoses come into the body. If you have not replaced those hoses, do that too.