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The RVer's Open Forum / GENERAL RV DISCUSSIONS / Banks vs Gibson exhaust mods; Ford 460

Paul Allerding
User ID: 0492334 Aug 14th 7:45 PM
My dealer wants $2320 installed for Banks Headers and exhaust (no intake mods). And they want $1770 installed for the Gibson headers and exhaust in stainless steel. For Gibson in aluminized they want $1266 installed. Gibson header flanges are 3/8" thick and use a gasket. Banks are 5/8" thick and don't use a gasket. There is no question in my mind that the Banks is the best, but I don't want to spend that much.

Does the Gibson give decent power improvement on the Ford 460 V8?

Will the 3/8" flange on the Gibson hold up or am I going to get leaks?

Are there other header/exhaust systems I should consider?

I heard that just replacing the muffler in the stock piping can produce a big gain, nearly as much as if the piping behind the manifolds are replaced. Is that true?

I have a 1990 E350 Class C with 85,000 miles which has never had a problem with the exhaust, but my newer 1997 Class A has a broken exhaust manifold stud at only 41,000 miles. How reliable are the stock exhaust manifolds?

Why would an exhaust manifold stud must snap off like that? I bought used so don't know the history, but that likely the previous owner towed with it.

jd
User ID: 8541163 Aug 18th 3:12 PM
Studs snap because the big long manifolds get longer [front to rear] with the heat of driving. Class A might have even worse air flow around the manifolds than Class C. Manifold goes to get "long", stud in the way, interferes, gets sheared. On our '84 Class C, passenger side 460 manifold was very warped, driver side slightly warped. Removed and had resurfaced at NAPA. Reinstalled with new stamped steel gaskets and new bolts with NeverSeez on all sliding surfaces. Torqued to about 25. So far, things are sliding OK, nothing broken or leaking. Connected manifolds to FlowMaster [www.flowmastermufflers.com] "cat back" exhaust system. '83 chassis didn't have a catalytic converter so I made up the length with pipe.
I hear good things about Doug Thorley Headers, now apparently part of Summit Racing. If I recall, Thorley and Flowmaster, or at least one of them, references the other, so you should be able to get them connected under your coach.
Our FM cat-back is a single 3" system, aluminized, and the muffler is massive. Full 3" all the way through, perfect bends in all the tubing. We gained some power and run a little cooler.
It's possible to abuse manifolds. How? Run hard on the open road, duck into a roadside restaurant, fuel stop or rest area without slowing down first or allowing the engine to idle. Shut down right away, expansion/contration go crazy.
Bank$ is well, "$", and a very good product. I wouldn't be afraid of 3/8" flanges, but I think I'd find out how robust the gaskets are. The plain automotive ones that look like asbestos probably will blow out. Stamped steel or speed shop stuff probably won't.
God Bless, jd

Paul Allerding
User ID: 2163744 Sep 1st 11:24 AM
I just had teh broken manifold stud repaired. Manifold was slightly warped at that end (probably from the stud being broken), so he put a gasket on it and it sealed up fine. Cost was $375. Sounds good now.

Now maybe a freer flowing muffler would help. But I will eliminate the resonator and just run the muffler. Will put the muffler up where the resonator goes so I don't mess with secondary pipe length. No catalytic converter on this one.

jd
User ID: 8541163 Sep 1st 12:45 PM
Paul,

I think that'll do it, especially if you relieve exhaust heat with a Cat-Back [in your case Crossover-Pipe-Back] exhaust like the FlowMaster I suggested earlier.

Be sure the cooling system is clean inside and out, fan clutch is good, fan shrouding is all in place, AND you don't impede airflow with a bug screen or the like.

Wondered where you'd been, glad you're making progress.

God Bless, jd

Paul Allerding
User ID: 2163744 Sep 1st 1:48 PM
If I do anything to the exhaust it likely will be to get rid of the resonator and put a Flowmaster 50 or 70 motorhome type muffler in (or possibly a Borla) it's place, leaving a straight pipe where the existing muffler is. I want the muffler in the resonator position because I read that the secondary pipe length is important to the power curve and I don't want to mess with that.

I left it in the shop one more day (today) and they are doing the cooling system and thermostat, along with a number of other items.

No bug screens. There is a place where the rubber divider between the front grille area and engine bay is pulled off and open. Is that divider important to cooling? I was thinking that more of it should come off to help channel incoming air into the engine bay for better cooling of the exhaust manifolds.

I have been very busy. Bought this Class A in late July after a month of waiting while I had the dealer do repairs of over $4000. They still sold it to me for their original asking price. They did all four brakes including two rotors and a caliper, complete tranny flush and filter, two rear Bilstein shocks, six new Michelin tires, generator muffler and tailpipe, new air con cover, fixed backup camera, and many smaller repairs including a torn seat. Had it back for some minor issues and not going back one more time in a week (hopefuly last time) for a water leak and the generator won't start. They are still fixing all this no charge even though the sale was "as is." Good dealer.

I really like this motorhome, but for manuverability--in that case I would like a 21 foot Class C, which we probably will get some years from now when the kids are off on their own.

Jim R
User ID: 0498634 Sep 17th 12:53 AM
Paul- Doug Thorley headers are a good buy they are hooked up with Gibson check on line they have a life time warranty and you can install them yourself I did and I'm no mechanic,they come with good instructions.Check them out before you spend the big bucks.Also with any good full flow muffler and you are good to go.I got lots of good advice of this site on what and what not do.
Jim

Barthbill
User ID: 1689844 Sep 29th 12:06 AM
Another happy Thorley user here. I have used them on several vehicles with great results.

Paul Allerding User ID: 0492334	Aug 14th 7:45 PM My dealer wants $2320 installed for Banks Headers and exhaust (no intake mods). And they want $1770 installed for the Gibson headers and exhaust in stainless steel. For Gibson in aluminized they want $1266 installed. Gibson header flanges are 3/8" thick and use a gasket. Banks are 5/8" thick and don't use a gasket. There is no question in my mind that the Banks is the best, but I don't want to spend that much. Does the Gibson give decent power improvement on the Ford 460 V8? Will the 3/8" flange on the Gibson hold up or am I going to get leaks? Are there other header/exhaust systems I should consider? I heard that just replacing the muffler in the stock piping can produce a big gain, nearly as much as if the piping behind the manifolds are replaced. Is that true? I have a 1990 E350 Class C with 85,000 miles which has never had a problem with the exhaust, but my newer 1997 Class A has a broken exhaust manifold stud at only 41,000 miles. How reliable are the stock exhaust manifolds? Why would an exhaust manifold stud must snap off like that? I bought used so don't know the history, but that likely the previous owner towed with it.
jd User ID: 8541163	Aug 18th 3:12 PM Studs snap because the big long manifolds get longer [front to rear] with the heat of driving. Class A might have even worse air flow around the manifolds than Class C. Manifold goes to get "long", stud in the way, interferes, gets sheared. On our '84 Class C, passenger side 460 manifold was very warped, driver side slightly warped. Removed and had resurfaced at NAPA. Reinstalled with new stamped steel gaskets and new bolts with NeverSeez on all sliding surfaces. Torqued to about 25. So far, things are sliding OK, nothing broken or leaking. Connected manifolds to FlowMaster [www.flowmastermufflers.com] "cat back" exhaust system. '83 chassis didn't have a catalytic converter so I made up the length with pipe. I hear good things about Doug Thorley Headers, now apparently part of Summit Racing. If I recall, Thorley and Flowmaster, or at least one of them, references the other, so you should be able to get them connected under your coach. Our FM cat-back is a single 3" system, aluminized, and the muffler is massive. Full 3" all the way through, perfect bends in all the tubing. We gained some power and run a little cooler. It's possible to abuse manifolds. How? Run hard on the open road, duck into a roadside restaurant, fuel stop or rest area without slowing down first or allowing the engine to idle. Shut down right away, expansion/contration go crazy. Bank$ is well, "$", and a very good product. I wouldn't be afraid of 3/8" flanges, but I think I'd find out how robust the gaskets are. The plain automotive ones that look like asbestos probably will blow out. Stamped steel or speed shop stuff probably won't. God Bless, jd
Paul Allerding User ID: 2163744	Sep 1st 11:24 AM I just had teh broken manifold stud repaired. Manifold was slightly warped at that end (probably from the stud being broken), so he put a gasket on it and it sealed up fine. Cost was $375. Sounds good now. Now maybe a freer flowing muffler would help. But I will eliminate the resonator and just run the muffler. Will put the muffler up where the resonator goes so I don't mess with secondary pipe length. No catalytic converter on this one.
jd User ID: 8541163	Sep 1st 12:45 PM Paul, I think that'll do it, especially if you relieve exhaust heat with a Cat-Back [in your case Crossover-Pipe-Back] exhaust like the FlowMaster I suggested earlier. Be sure the cooling system is clean inside and out, fan clutch is good, fan shrouding is all in place, AND you don't impede airflow with a bug screen or the like. Wondered where you'd been, glad you're making progress. God Bless, jd
Paul Allerding User ID: 2163744	Sep 1st 1:48 PM If I do anything to the exhaust it likely will be to get rid of the resonator and put a Flowmaster 50 or 70 motorhome type muffler in (or possibly a Borla) it's place, leaving a straight pipe where the existing muffler is. I want the muffler in the resonator position because I read that the secondary pipe length is important to the power curve and I don't want to mess with that. I left it in the shop one more day (today) and they are doing the cooling system and thermostat, along with a number of other items. No bug screens. There is a place where the rubber divider between the front grille area and engine bay is pulled off and open. Is that divider important to cooling? I was thinking that more of it should come off to help channel incoming air into the engine bay for better cooling of the exhaust manifolds. I have been very busy. Bought this Class A in late July after a month of waiting while I had the dealer do repairs of over $4000. They still sold it to me for their original asking price. They did all four brakes including two rotors and a caliper, complete tranny flush and filter, two rear Bilstein shocks, six new Michelin tires, generator muffler and tailpipe, new air con cover, fixed backup camera, and many smaller repairs including a torn seat. Had it back for some minor issues and not going back one more time in a week (hopefuly last time) for a water leak and the generator won't start. They are still fixing all this no charge even though the sale was "as is." Good dealer. I really like this motorhome, but for manuverability--in that case I would like a 21 foot Class C, which we probably will get some years from now when the kids are off on their own.
Jim R User ID: 0498634	Sep 17th 12:53 AM Paul- Doug Thorley headers are a good buy they are hooked up with Gibson check on line they have a life time warranty and you can install them yourself I did and I'm no mechanic,they come with good instructions.Check them out before you spend the big bucks.Also with any good full flow muffler and you are good to go.I got lots of good advice of this site on what and what not do. Jim
Barthbill User ID: 1689844	Sep 29th 12:06 AM Another happy Thorley user here. I have used them on several vehicles with great results.