Class a exhaust

[Shawnski0414]

Good evening everyone . Last year I bought a 1994 Damon challenger p30 chassis with Chevy 454. It has a manifold leak which I’ve come to realize is very common in these. Can anyone suggest a good muffler system? I’ve read a lot about people switching to headers. Thanks! If anyone has done this how are the performance improvements?

 

[Kirk]

I haven't put an exhaust system on a 454, but I did have a Banks exhaust header and exhaust put on a 99 F53, V-10 and the improvement was great. I suspect that would be true for your 454 and it should eliminate the problems with the manifold warping. Unfortunately, when I looked up the 454 on the Banks site, they no longer make headers for it. Checking further, I did find them available from Amazon.

Amazon.com : 454 Headers

 

[8Muddypaws]

Prepare yourself for sticker shock when you find out how much they cost to get installed.

 

[darsben]

I did the same on my class A. Have not regretted it in 2 years. It did not improve performance per se BUT it was a cure for other problems

 

[TheBar]

Prepare yourself for sticker shock when you find out how much they cost to get installed.

X2. Read this post.

 

[Ex-Calif]

I have the same engine, basically. I would not personally switch to headers. My exhaust system has held up 25 years and 60k+ miles. I would just get the stock gaskets replaced.

I would not wait too long. Exhaust impinging on the head face or the manifold face will cause erosion and pitting. Ultimately this will make the surface of the head unusable and require a machining repair.

 

[Gary RV_Wizard]

I'm probably tech-nitpicking, but you mentioned a manifold leak but inquired about a muffler system and then asked about headers. All different things. That mixed set of terms is likely to bring you confusing answers. The "muffler system" is a collection of pipes and sound-deadeners that is downstream from the "exhaust manifolds". You don't need a new muffler system to fix a manifold leak problem. A "header" is more sophisticated (and expensive!) version of a vanilla exhaust manifold, designed to improve engine performance by streamlining the exhaust gas flow.

As Ex-Calif says, you need to fix the exhaust manifold leak. That could be as simple as needing a new gasket or as bad as a replacement manifold and/or re-machining the cylinder head, but all of those involve a lot of labor hours in addition to parts. Probably more total cost than a '94 Challenger is worth unless you can DIY.

If you choose to replace the stock manifold with a header-type manifold, the labor effort/cost is similar but the header part is probably substantially greater. I doubt if you would realize enough performance benefit to justify it, even though it would be superior.

Difference Between Headers & Manifolds - Intake Manifold vs Exhaust Manifold - AutoAnything

As you first dive into the world of car modification, you’re tossed into a massive word salad with all sorts of words, terms, and acronyms that you’re supposed to know, but no one really ever takes the time to explain them. When exploring the world of bolt-on modifications, you’ll see these...

www.autoanything.com

 

[darsben]

headers do not have to be as expensive as a banks system. I got a set for under $850 INSTALLED the came from NAPA. The headers stopped the overheating of my spark plug wires and lowered temps in my dog house. The guy installed them by removing the front tires.

 

[Ex-Calif]

Not all headers will provide a performance improvement. Also headers are usually designed to fit a specific engine bay. You need to make sure the headers will fit the engine bay and at some point connect to the original exhaust system.

Headers also have various quality. Cheap poorly designed headers may have thin manifold flanges subject to warping and then you are right back with an exhaust leak.

All in all just make sure you understand why you are switching to headers, what the pros and cons are and do your research to make sure you are not more unhappy than before.

The 454 rams horn manifold is not a terrible manifold.

 

[Shawnski0414]

Thx for all the replies. It’s a gasket leak on both sides. Estimate I got was for 1900. Seen and read some things about headers solving the gasket problem as people have replaced them multiple times.

 

[Charlie 5320]

$1900 to fix the leaking manifolds or putting on a set of headers? If it's for fixing the leak, you better find somebody else, because they don't want your job. Even IF they broke every bolt taking the manifolds off it wouldn't take more than a couple days to drill and tap the holes. I had both sides off of my old Winnebago several years ago and only broke 4 of the bolts off. Bout a day and a half with filing the manifolds flat again, they were both warped. I'm another that WOULDN'T use headers on a MH. NOT worth the expense, and they won't last near as long as a set of manifolds.

 

[Gary RV_Wizard]

Well, Charlie, 1-1/2 days of professional shop labor runs around $1200-$1600. So $1900 doesn't sound so outlandish afterall.

 

[Gary RV_Wizard]

Not all headers will provide a performance improvement. Also headers are usually designed to fit a specific engine bay. You need to make sure the headers will fit the engine bay and at some point connect to the original exhaust system.

But if they do not improve it in some way, why spend the extra $$ for them vs the plain old factory cast iron exhaust manifolds? The whole idea of a "header" is to provide individual tuned exhaust tubes rather than simply dumping the exhaust into a common plenum where the turbulence from other ports inhibits a smooth exhaust flow. It's that custom design & fitting adds greatly to the cost

Performance in this context includes the whole gamut, e.g. improved fuel efficiency, power, temperature, etc.

 

[Shawnski0414]

$1900 to fix the leaking manifolds or putting on a set of headers? If it's for fixing the leak, you better find somebody else, because they don't want your job. Even IF they broke every bolt taking the manifolds off it wouldn't take more than a couple days to drill and tap the holes. I had both sides off of my old Winnebago several years ago and only broke 4 of the bolts off. Bout a day and a half with filing the manifolds flat again, they were both warped. I'm another that WOULDN'T use headers on a MH. NOT worth the expense, and they won't last near as long as a set of manifolds.

It was to repair them.

 

[Shawnski0414]

It was the only place I could find that would do them. Nobody wants the job due to the bolts breaking.

 

[Utclmjmpr]

Soak the studs with 1/2 & 1/2 ATF and MEK mix for a couple days,, best penetrant known..>>>Dan

 

[Shawnski0414]

I'm probably tech-nitpicking, but you mentioned a manifold leak but inquired about a muffler system and then asked about headers. All different things. That mixed set of terms is likely to bring you confusing answers. The "muffler system" is a collection of pipes and sound-deadeners that is downstream from the "exhaust manifolds". You don't need a new muffler system to fix a manifold leak problem. A "header" is more sophisticated (and expensive!) version of a vanilla exhaust manifold, designed to improve engine performance by streamlining the exhaust gas flow.

As Ex-Calif says, you need to fix the exhaust manifold leak. That could be as simple as needing a new gasket or as bad as a replacement manifold and/or re-machining the cylinder head, but all of those involve a lot of labor hours in addition to parts. Probably more total cost than a '94 Challenger is worth unless you can DIY.

If you choose to replace the stock manifold with a header-type manifold, the labor effort/cost is similar but the header part is probably substantially greater. I doubt if you would realize enough performance benefit to justify it, even though it would be superior.

Difference Between Headers & Manifolds - Intake Manifold vs Exhaust Manifold - AutoAnything

As you first dive into the world of car modification, you’re tossed into a massive word salad with all sorts of words, terms, and acronyms that you’re supposed to know, but no one really ever takes the time to explain them. When exploring the world of bolt-on modifications, you’ll see these...

www.autoanything.com

If it doesn’t improve performance why do you say it is superior? What are the negatives to headers aside from the price? Most of the things I’ve read say they solved manifold gasket leaks and improved performance and mpg. Only goin by things I’ve read which is why I’m asking

 

[Gary RV_Wizard]

I didn't say it doesn't increase performance; I said it probably doesn't improve enough on a motorhome to justify the extra cost. Motorhome "performance" isn't like that of a hot rod - it's always operating near its max weight limits and ain't never going to win a race. Improving the exhaust scavenging from the cylinders might gain a few tenths of an mpg or gain a couple mph climbing hills, but that's hardly noticeable except maybe for bragging rights. You decide what it is worth in $$.

High quality headers are generally machined to higher tolerances than mass-produced manifolds and the people who install expensive components typically do more than just bolt them on without milling the heads. But you can do that with any installation - it's not "header magic". A good engine shop would mill the matching surfaces and use a high quality gasket to insure a tight fit.

 

[dktool]

Motorhome "performance" isn't like that of a hot rod - it's always operating near its max weight limits and ain't never going to win a race. Improving the exhaust scavenging from the cylinders might gain a few tenths of an mpg or gain a couple mph climbing hills, but that's hardly noticeable except maybe for bragging rights.

To this I will add the fact that this engine is the GEN 5 of the 454, it's a small cam, peanut port smog motor that has no lungs anyway so headers will sound good but that is all.
You're better served spending that $$ on gas.

I'm guessing your failed manifold is on the passenger side ?

 

[Kirk]

I didn't say it doesn't increase performance; I said it probably doesn't improve enough on a motorhome to justify the extra cost.

While I might agree with that in some cases, it just is not true as a blanket statement. The post asked about headers to resolve manifold issues and because they get the hot exhaust away more quickly they often do that quite well. There is a wide range of header systems available for a wide range of prices.

There have in fact been other engines that headers made a significant power/performance in, and a good example was the early Ford V-10. Having owned a 99 F-53 with the V-10 which I had the Banks system added to, I can assure you that there are situations where it is true. I added the Banks in early 2000 and kept the F-53 until 2012 when I sold it to a new owner. The last that I heard from then was in 2016 when they were still using it.
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