1968 390 z code exhaust leak

I just bought a 68 XL with the z code. It had an exhaust leak on the pass side. I read that these engines are somewhat prone to this problem to the point that sometimes if you let it go, the head needs to be milled to flatten the exhaust surface. I brought it to my mechanic who snapped a manifold bolt, retapped it, surfaced the head (still in the car) and the manifold with a 3m pad, reinstalled the manifold with a new felpro gasket and it still leaks.

He says that to fix it right, he'd have to remove the head and have it milled. OK, but then you might figure, why not take both off and have them rebuilt. He says that the FE engines don't take well to having just the top end redone, and that the increased compression will blow out the rings necessitating a total rebuild any way. He suggests I just live with it until I want to make the big investment.

Two questions: I assume that the exhaust leak will continue to damage the head surface. Will it also screw up the exhaust valve? Also, is there any truth to the new top end screwing up the old bottom end story? I gave this guy $300 for 6 hours of labor to fix a problem that isn't any better.

Thanks for your help,

Jason

I dont know if the exhaust leak will hurt the exhaust valve or not, but rebuilding the top end shouldent hurt the rings on a high millage bottem end. I had my 390 heads rebuilt at about 65K and im at 105K now and my engine runs better than it ever has (it dosent burn oil and I have good compression). The only way your going to get your exhaust manifolds to seal for good is to buy some copper exhaust manifold gaskets from jeg's (like 30$, but worth every cent). I did this and it solved my problem for good. I even reused them once and they still worked flawlessly. Befor I had my heads rebuilt I had a bad exhaust leak using felpro gaskets and I could never get them to seal for more than 3 weeks. when I had to have my heads rebuilt I found it was because of a cracked exhaust valve, so the leak may have contributed to the cracked valve. Befor you have your top end rebuilt buy some copper exhaust manifold gaskets you will be happy. [img]/phpBB/images/smiles/icon_smile.gif[/img] Brian K.

<font size=-1>[ This Message was edited by: 67bullitt on 8/19/02 10:58pm ]</font>

I got a 289 with an all aluminum top end and stock bottom end. Until I get the money for the 347 stroker kit. NO PROBLEMS AND IT RUNS STRONG!