Has anyone tried header exhaust gaskets? I need to replace my stock gaskets which have burned up and I wonder if there is anything better. Also, seems my right and left exhaust manifolds have different gaskets. The right has a flat gasket and the left a donut. Is anyone familiar with the flat gasket and how to replace it?
Header gaskets might help temporarily but if manifold surface is rough and not true, a surface grind is in order. As far as the flat gasket, that is meant to mate with the flat side of the heat riser. The other side of the heat riser uses a "donut". Is your heat riser there, or is it missing?
Exhaust gaskets in general are supposed to live many years. If there is a leak due to poor alignment, warping or loose bolts, fix that first. The built up exhaust gasses create a pressure, then create a jet of hot air, which in turn creates a groove then a blown hole (and noise). Once flattened and fixed, the replacement gaskets will last even longer.
390 log style manifolds warp, believe it. Also even the port surfaces on the head can get pitted with age. I've heard of people using a soft copper gasket that can crush a bit to take up some of the irregularities but I have no experience personally so "caveat emptor" Stu
My 64 developed an exhaust leak. After doing a little web research, it seems that a gasket was not fitted from the factory.
I removed the bad gasket, cleaned the surfaces and re-installed the manifold using Ultra Copper RTV. That was about 6 months ago and it is still not leaking.
Ultra Copper RTV is "copper silicone" chaulking for lack of a better description. Look in the parts store where you'd buy gasket silicone in a tube etc. RTV just means "room temperature vulcanizing" As for the copper gaskets I'm not sure where one might get them maybe a speed shop or Summit etc. Good Luck. Stu
Like CaptV says, make sure they are square and flat. Check them with a straight edge. I had to plane both of mine at a machine shop because I couldn't get them to seal. Previous owner doubled up on the gaskets to get them to seal. That worked for a couple years, until they blew out and I had to fix them properly.
Also, spray the outside with that grey graphite dry lubricant stuff just prior to installation. It won't burn off like paint and makes the manifolds look like new cast iron!
<font size=-1>[ This Message was edited by: Gordo on 10/7/06 2:06pm ]</font>