Can a bad intake manifold gasket make my exhaust really loud?

I bought my '56 Special last November and the exhaust was really loud on the original 322 Nailhead. There was a crack in one of the exhaust manifolds so I replaced it but it's still just as loud. I don't see any cracks in the other exhaust manifold and all of the bolts are tight. I was at a cruise last night and asked a couple of guys what they thought and they both said it's probably the intake manifold gasket. How could that make it loud? If that's the problem how hard is it to replace? If I've never done it before should I try and replace it or should I try to find someone who knows what they're doing? Thanks in advance....

 

Take an old towel or some rags and stuff it all around the manifold and intake until you muffle the noise and look there......Intake manifold gasket is a snap, even for a first timer.
Roll under the car and check your muffler and piping.

 

The car was restored in 1997 and there's only 7,000 miles on it since. It has a nice stainless exhaust system on it that looks brand new. I'll try the towel idea tomorrow. If that plug is bad can I buy another one or will the whole manifold need to be replaced?

 

I think the '56 has a plate on the bottom of the intake that rusts out, it's called a core plug on the '60, Russ Martin has them just did one over the weekend was able to use the original one!

 

I put several rags under the front and back of the manifold and along both sides but it's still as loud as it was before. I revved it up pretty good and none of the rags moved at all. The engine only has 7,000 miles on a complete rebuild so the manifold wouldn't deteriorate that quickly, would it? What should I try next? Thank you to those who responded.... :TU:

 

Late 55 and 56 322's had the plate on the bottom along with an exhaust track under the carburetor. Rebuild kits will have a gasket for the plate, so a lot of us will have an extra after rebuilding the earlier 322. A replacement plate can be easily fabricated (and will not show) if an original can not be found.

 

I don't know what that is. If that was bad would it still be loud after I put the rags all the way around the manifold? Wouldn't the rags at least move a little when I rev it up?

 

Can someone please post a pic of what the "exhaust crossover under the carburetor" looks like on a '56 Nailhead 322 with a Carter carb? I checked several other threads on this site with "exhaust crossover" in the title but I think they were talking about the exhaust system under the car. I couldn't find anything on YouTube either. Thanks....

 

Notice that there are twelve runners on the manifold base.
the eight larger runners are the intakes.
the four smaller runners are where the exhaust gases run under the intake runners. Heating the floor of the manifold

 

Thanks for the pics. So how do I block them off? One guy said to use freeze plugs but wouldn't they be too big? If the engine rebuild only has 7,000 miles on it should this be a problem already?

 

I wouldn't block them off. The heat is important for vaporizing the fuel. And for faster warm up.

Right Adam. If that's the source of the leak. A new plate and/or gaskets would be in order. Then no worries

 

You still have to locate noise and leak before you can fix it.

 

What I don't understand is if the exhaust goes out the manifolds and into the exhaust pipes, through the mufflers and out the tail pipes how does it come in contact with the intake manifold?

 

reference the photos in post #13
note that there are 12 ports on the intake.
the four smaller ports connect to the exhaust ports and crossover, connecting the exhaust ports of each head to the other head.
The presence of the hot exhaust in the manifold provides the needed heat to the fuel mixture.