Other Cadillac Engines Discussion, 67 DeVille 429 Exhaust Manifold Gaskets in Cadillac Engine Discussion; Car runs great but I can't get the (factory spec) exh manifold gaskets to last more than about 5k miles. ...
Car runs great but I can't get the (factory spec) exh manifold gaskets to last more than about 5k miles. Can't seem to locate any "tougher / header-type"
gaskets that'll fit. Don't mind spending a few extra $$ on copper or aluminum gaskets - anyone know who or how such a set could be "custom made" ?
Have you tried stacking two new oem exhaust gaskets together? Your exhaust manifolds may have warped from the heat over the years. Two gaskets stacked together would help fill any voids. You may also want to clean and torque the exhaust manifold bolts to 35 lb/ft during installation.
My '73 Cadillac had a cracked exhaust manifold. I found a replacement set, and after having them machined straight I painted them with Eastwood exhaust paint and had them installed w/o any gaskets, at the "suggestion" of my mechanic. No leaks yet. Question - did you have the bolts retorqued after a couple hundred miles?