Header Gaskets

[slowburb]

What works for me is to torque them cold, run the truck, torque them hot, and repeat in a few days. They're not going to grip deep enough into the threads to "lock" in the heads until they heads are expanded from heat and then contract as they cool. You can think you have them tight enough (when cold) that they will break if you wrench on them any more, but when everything is hot you can easily get another 1/4 or 1/2 turn on each bolt. That's when they're right.

 

[mrstang01]

Do you have a part number for the 350 and/or a preferred vendor?

Michael

I'm telling you...this is what you want:

The Percy's Seal-4-Good Reusable Flange Gaskets are multi-layered and made from a special "Dead Soft" Aluminum, which conforms to header flanges for the ultimate seal. Since the Seal-4-Good is made from multiple layers of dead soft metal, it easily conforms to small imperfections that a copper gasket simply can not. Due to this construction, these gaskets will not blow out or burn out when properly installed.

Percy's Seal-4-Good collector gaskets are referred to, by many, as the "best on the market". These "Dead Soft" aluminum gaskets seal far better than competitive copper gaskets. Available in 2 1/2", 3", and 3 1/2" sizes.

 

[kennythewelder]

This is what I'm running. They are almost twice as thick as exhaust maniflod gaskets.
https://www.amazon.com/FEL-PRO-INC-...1404&qid=1537316280&s=Automotive&sr=1-2-fkmrn

This is for a 350