Exhaust advice

[Matt Conlan]

Good day! Got a '70 Newport Custom 2dr HT. 2bbl Holley 383. Looks like someone did a Waldron's stainless dual exhaust about 25-30 years ago. It looks (and smells) like Ive got a crack in the passenger side exhaust manifold. Any reason to replace with other than OEM cast iron? It's just a summer cruiser to me, but I don't mind upgrading if there's value in it. Looks like there are some used ones available on this site.

Just seeing what others have decided on. May throw on a 4 bbl Holley (just because I have one in my garage) but not planning any major engine upgrades.

Thanks!

 

[rags]

another member here thought he had the same problem. turned out it was loose nuts. if it is cracked, i'd replace it with the same.

 

[Matt Conlan]

Thanks! I guess I'll take it off and have a look.

 

[live4theking]

If the front and rear did come out they go into the water jacket and you'll need to reinstall them with thread sealer.

 

[furious70]

Sounds like a $20 replacement lopo log would be fine for your application if you end up needing it

 

[Matt Conlan]

Ah, good point on the penetrations, and, I'm sorry, but lopo log?

 

[furious70]

Just replace like for like, no need to buy hp manifolds or headers

 

[CBODY67]

BEFORE you remove the manifold, FIRST get a wrench and check the tightness of the rear nuts. Sometimes, they get about 1/3 turn loose and it causes a sound like a cracked manifold. IF the manifold is really cracked, I would suspect it might get quieter as the engine heats up?

From my experiences,
CBODY67

 

[Matt Conlan]

Now that I'm thinking about it, the noise isn't THAT bad but there's a lot of smoke coming from under the manifold. It doesn't smell like coolant or oil, but maybe its burning something off? Thanks for the ideas. I'll play with it this weekend and let you know what I find.

 

[darth_linux]

Ah, good point on the penetrations, and, I'm sorry, but lopo log?

Low performance “log” style manifolds (the standard equipment).

 

[rags]

Exhaust manifold gasket leaking

Hello gents, My exhaust manifold is leaking on the driver side. I can hear it tick on startup, and I've used the old rubber hose stethoscope to isolate the spot. When it warms up, the ticking stops, but I'm thinking that I smell exhaust fumes in the cabin. So what is the method of...

www.forcbodiesonly.com

 

[Boydsdodge]

Now that I'm thinking about it, the noise isn't THAT bad but there's a lot of smoke coming from under the manifold. It doesn't smell like coolant or oil, but maybe its burning something off? Thanks for the ideas. I'll play with it this weekend and let you know what I find.

Valve cover gasket leaking will cause smoke from manifold, bigger the leak bigger the smoke.

 

[polaratherapy]

Valve cover gasket leaking will cause smoke from manifold, bigger the leak bigger the smoke.

Just went through the exact scenario Boydsdodge describes this week.
Preping my 67 Newport for it's safety, found I had not properly installed one valve cover, removed it , cleaned it , JB weld gasket goop.
All good now, no more smoke, it was dripping on the exhaust manifold

 

[Big_John]

Gotta agree with everyone about loose nuts and throw this in... If someone in the past used gaskets under the manifolds (the factory didn't), there's a good chance those are starting to blow out.

 

[darth_linux]

Gotta agree with everyone about loose nuts and throw this in... If someone in the past used gaskets under the manifolds (the factory didn't), there's a good chance those are starting to blow out.

wait, there were no exhaust manifold gaskets originally?

 

[Big_John]

wait, there were no exhaust manifold gaskets originally?

That is correct for the big blocks. Small block engines did get exhaust manifold gaskets.

I've never seen any exhaust gasket, including the fancy RV versions, last.

 

[Matt Conlan]

Good stuff, guys. Thanks! The valve cover gaskets are relatively new, but I'll certainly check it out. The smoke is coming from the back nearest the firewall, so Hopefully its one of the things mentioned. I'll report back.

 

[Boydsdodge]

Just went through the exact scenario Boydsdodge describes this week.
Preping my 67 Newport for it's safety, found I had not properly installed one valve cover, removed it , cleaned it , JB weld gasket goop.
All good now, no more smoke, it was dripping on the exhaust manifold

I will be doing the valve cover gasket on Tux today for the drip.

 

[Boydsdodge]

Good stuff, guys. Thanks! The valve cover gaskets are relatively new, but I'll certainly check it out. The smoke is coming from the back nearest the firewall, so Hopefully its one of the things mentioned. I'll report back.

New gaskets leak, I know. Right rear is number one spot for BB to leak cover.

 

[Elvis Lean Burn HP]

what type/style of valve cover gaskets are you guys using? I would rather not use the Traditional cork gaskets. I have the typical smoke on a 77 400 high-performance labor and of course. Any thoughts?