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Thorley Headers
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Supporting Member of Barthmobile.com 6/12
Formally known as "Humbojb"
Picture of Jim and Tere
posted
Anyone have a set of Thorley headers for a 454? 1989 Barth, 1988 P30 chassis


Jim and TereJim and Tere

1985 Regal
29' Chevy 454 P32
8411 3172 29FP3B
Gear Vendor 6 Speed Tranny
 
Posts: 3915 | Location: madisonville tn usa | Member Since: 02-19-2005Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 6/12
Formally known as "Humbojb"
Picture of Jim and Tere
posted Hide Post
The part number would be 303y-c


Jim and TereJim and Tere

1985 Regal
29' Chevy 454 P32
8411 3172 29FP3B
Gear Vendor 6 Speed Tranny
 
Posts: 3915 | Location: madisonville tn usa | Member Since: 02-19-2005Reply With QuoteReport This Post
Picture of BarthBluesmobile
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I see a set on Ebay, and Summit Racing is quoting a ship date of July 16.
Matt


1987 Barth 27' P32 Chassis
Former State Police Command Post
Chevrolet 454
Weiand Manifold, Crane Cam, Gibson Exhaust
 
Posts: 451 | Location: Massachusetts | Member Since: 07-28-2006Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 6/12
Formally known as "Humbojb"
Picture of Jim and Tere
posted Hide Post
Yes, but I'm trying not to spend that kind of money.


Jim and TereJim and Tere

1985 Regal
29' Chevy 454 P32
8411 3172 29FP3B
Gear Vendor 6 Speed Tranny
 
Posts: 3915 | Location: madisonville tn usa | Member Since: 02-19-2005Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 7/17
Picture of Doorman
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Is there a reasons you need headers on your coach?


1986 31' Regal -1976 Class C
454/T400 P30 -350/T400 G30
twin cntr beds - 21' rear bath
 
Posts: 1029 | Location: Dayton, Ohio | Member Since: 09-27-2009Reply With QuoteReport This Post
Picture of BarthBluesmobile
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On mine, the exhaust manifolds were rotted through, and I guess with hindsight, I can say there was a mix of "want" and "need" in the decision.

Your mileage may vary!
Matt


1987 Barth 27' P32 Chassis
Former State Police Command Post
Chevrolet 454
Weiand Manifold, Crane Cam, Gibson Exhaust
 
Posts: 451 | Location: Massachusetts | Member Since: 07-28-2006Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 6/12
Formally known as "Humbojb"
Picture of Jim and Tere
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Well,the doughnuts between the existing exhaust header and the exhaust pipe have to be replaced, so---. I think you're right. If it ain't broke, don't fix it. I don't think the existing exhaust manifold is leaking yet. It's up to Tere.

Jim


Jim and TereJim and Tere

1985 Regal
29' Chevy 454 P32
8411 3172 29FP3B
Gear Vendor 6 Speed Tranny
 
Posts: 3915 | Location: madisonville tn usa | Member Since: 02-19-2005Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 1/21
Picture of Steve VW
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The performance of the headers is slightly better, especially at high throttle settings. Being tubular as opposed to cast iron, they are much lighter as well. Neither of these is that important in a motor home.

For me the biggest downside to the cast manifold is their heat retention. When you heat 100 lbs of thick cast iron to near red hot it takes it a long time to cool down. In a confined motor home engine bay this means the wiring, hoses and fuel system stay hot a lot longer. Especially hard on spark plug wire ends.

The extended heat soak also tends to evaporate the fuel in the carburetor bowl and fuel lines. Hard starting and vapor lock can result.

The thin tubular headers cool down much more quickly, reducing the heat soak effects. (They are also lighter and easier to install!)

If I had iron manifolds with crack or corrosion problems I would surely replace with the headers. If the manifolds are ok I would be inclined to keep using them. Between cost of headers and labor to install, it is not trivial job.

In terms of performance and reliability it might be wise to spend money on new alternator, power steering pump, water pump, starter, etc since these are more likely leave you stranded somewhere than a manifold problem. hmm


9708-M0037-37MM-01
"98" Monarch 37
Spartan MM, 6 spd Allison
Cummins 8.3 300 hp
 
Posts: 4706 | Location: Kalkaska, MI | Member Since: 02-04-2011Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 1/21
Picture of Duane88
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The problem with removing the manifolds on Nose was I broke the bolts they were badly corroded an extra $200 to have them removed from the heads...


25 Ft Glassnose, 2792, 1982
454 Engine
Plain Jane Interior
Original Paint
Picture by Kevin

Regal
25CG3 3570 1988
 
Posts: 1687 | Location: Clinton Iowa | Member Since: 04-02-2017Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 7/17
Picture of Doorman
posted Hide Post
Any exhaust shop should not have a problem replacing manifold/pipe gasket.


1986 31' Regal -1976 Class C
454/T400 P30 -350/T400 G30
twin cntr beds - 21' rear bath
 
Posts: 1029 | Location: Dayton, Ohio | Member Since: 09-27-2009Reply With QuoteReport This Post
Picture of BarthBluesmobile
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You can get the Flowtech 11530 for under $200 with no shipping charge on Ebay. Flowtech is a Holley brand. It won't support the AIR hardware. As compared to 15 years ago, the availability and choices seem limited for 454 headers now. I think Gibson got out of the header business, at least for the 454.

The 69130 from Hedman is also on Ebay for $250. I think of this brand as being "better". But check the specs and I think the most important spec, is "how thick is the cylinder head flange". You don't want to have to continually tighten the header bolts. With the Gibsons, I have never had to.

Happy Motoring,
Matt


1987 Barth 27' P32 Chassis
Former State Police Command Post
Chevrolet 454
Weiand Manifold, Crane Cam, Gibson Exhaust
 
Posts: 451 | Location: Massachusetts | Member Since: 07-28-2006Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 1/21
Picture of Duane88
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Hey Tere, the 88 Regal I just got has a digital dash board does yours, wondered if this was standard. I would ask Jim but thought I would go directly to the expert....

Sorry about the thread drift!!


25 Ft Glassnose, 2792, 1982
454 Engine
Plain Jane Interior
Original Paint
Picture by Kevin

Regal
25CG3 3570 1988
 
Posts: 1687 | Location: Clinton Iowa | Member Since: 04-02-2017Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 6/12
Formally known as "Humbojb"
Picture of Jim and Tere
posted Hide Post
No. The original owner had Barth build this one with an older design that they had had before. He didn't like the newer dash so mine is not digital.


Jim and TereJim and Tere

1985 Regal
29' Chevy 454 P32
8411 3172 29FP3B
Gear Vendor 6 Speed Tranny
 
Posts: 3915 | Location: madisonville tn usa | Member Since: 02-19-2005Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 6/12
Formally known as "Humbojb"
Picture of Jim and Tere
posted Hide Post
quote:
Originally posted by Duane88:
Hey Tere, the 88 Regal I just got has a digital dash board does yours, wondered if this was standard. I would ask Jim but thought I would go directly to the expert....

Sorry about the thread drift!!


Reminds me of an old joke where the policeman asked the guy who crashed the motorcycle on a San Francisco hill, what happened. The response was,"Me know no, me know tell, me push button, go like hell".
This is Jim. Also now accused by someone somewhere of being racist.


Jim and TereJim and Tere

1985 Regal
29' Chevy 454 P32
8411 3172 29FP3B
Gear Vendor 6 Speed Tranny
 
Posts: 3915 | Location: madisonville tn usa | Member Since: 02-19-2005Reply With QuoteReport This Post
Supporting Member of Barthmobile.com 6/12
Formally known as "Humbojb"
Picture of Jim and Tere
posted Hide Post
Wonder why Hedman and Flowtech are so much cheaper?

Jim


Jim and TereJim and Tere

1985 Regal
29' Chevy 454 P32
8411 3172 29FP3B
Gear Vendor 6 Speed Tranny
 
Posts: 3915 | Location: madisonville tn usa | Member Since: 02-19-2005Reply With QuoteReport This Post
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