E-Bodies.org Cuda Challenger Forum

Technical Shop => Exhaust => Topic started by: 73chalngr on October 06, 2018, 04:23:57 PM

Title: 340 exhaust manifold
Post by: 73chalngr on October 06, 2018, 04:23:57 PM
Does anyone know the correct size of the bolts for the exhaust flange for a 340 with the 1970 manifolds . My gasket failed and my bolts seem a little small the nut side had washers  and the washers are bent a little bit Like they were undersized  bolts and nuts .
Title: Re: 340 exhaust manifold
Post by: Rich G. on November 09, 2018, 08:32:13 PM
The flange bolts are 7/16 . The manifold to head are 5/16
Title: Re: 340 exhaust manifold
Post by: Topcat on November 09, 2018, 08:41:06 PM
It's true you don't need gaskets and just use a sealer.

Some like using an exhaust gasket.
If you decide to, use the Cometic Copper ones.

They work excellent and seal very well and don't burn out.
Title: Re: 340 exhaust manifold
Post by: Dakota on November 10, 2018, 12:56:32 AM
Quote from: Chryco Psycho on November 09, 2018, 06:54:46 PM
unless you have the heat sheild gasket on the left side you are far less likely to have a leak if you do not use a gasket & just a thin layer of Ultra copper silicone sealer instead , Gaskets cause leaks

I have the heat shield.   Ultra copper on both sides of the heat shield, gaskets on both sides, or something else?
Title: Re: 340 exhaust manifold
Post by: Chryco Psycho on November 10, 2018, 03:44:06 AM
just Ultra copper on both sides of the shield
Title: Re: 340 exhaust manifold
Post by: Morty426 on November 10, 2018, 03:49:56 AM
How come you guys keep taking about the shield and how the manifold attaches to the head?

This guy want to know the size of the flange bolts - manifold to exhaust pipe. 

:wrenching:
Title: Re: 340 exhaust manifold
Post by: 73chalngr on November 13, 2018, 06:44:59 AM
Thanks for responding . Way back in 1990 when my motor was put together we had no idea what to do so I think we used a set of header gaskets we had  .