High Flow Quiet Exhaust

Right now the Factory Exhaust manifolds is all that is needed present.
Dual exhaust.
Walker Super Dyno Max Mufflers.

Summit Racing Sells them. In stock.
 
I'm trying to find an article I came across a few days ago about restomoding the '68 & '69 Catalinas. It stated that they are virtually the same (under the hood layout) as the '66 - '67 Tempest - GTO plus a little more room. I was surprised to read that the '68 Catalina convertibles weigh in a little under 4,000 lbs. I thought they would be much heavier
 
I'm trying to find an article I came across a few days ago about restomoding the '68 & '69 Catalinas. It stated that they are virtually the same (under the hood layout) as the '66 - '67 Tempest - GTO plus a little more room. I was surprised to read that the '68 Catalina convertibles weigh in a little under 4,000 lbs. I thought they would be much heavier
Check Hemming Motor News posted articles.
They are Very Well Written.
I have ran across Pontiac Facts there.
They cover The Big Pontiacs like your 1968 Catalina Ragtop & My 1963 Grand Prix.
 
Check Hemming Motor News posted articles.
They are Very Well Written.
I have ran across Pontiac Facts there.
They cover The Big Pontiacs like your 1968 Catalina Ragtop & My 1963 Grand Prix.

I wish I saved my old HMN, I'll have to check out if they archive the articals.
 
Download-File
The exhaust size looks small coming right off the manifold. What is it, 2" it even looks like less. Not mandrel bent, very restrictive looking. Mufflers are small, the whole system looks like there is plenty of room. Everything is welded together so it's trashed removing it all. Is there a Pontiac OE cast manifold that is larger exhaust but bolts right up to this block.
 
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The HO 421 & 428 & 455 & 400 RAM AIR& RAM AIR 4 ARE 2-1/2" OUTLET EXHAUST MANIFOLDS.
REQUIRED FOR 2-1/2" DUAL EXHAUST.
 
The HO 421 & 428 & 455 & 400 RAM AIR& RAM AIR 4 ARE 2-1/2" OUTLET EXHAUST MANIFOLDS.
REQUIRED FOR 2-1/2" DUAL EXHAUST.
So will any of these exhaust manifolds bolt up to my 400 and the exits point in the same direction so I can install factory shaped dual exhaust pipes?
 
If I'm replacing a restrictive exhaust I might as well go up from 2" to 2 1/2" with the Walker mufflers and perhaps an "H" pipe?
 
When I have time I will photograph 1970 455 360 Hp 500Ft/lbs Bonneville Convertible exhaust manifolds.....
And HO 421 1965 2+ 2 exhaust manifolds I have here too.
Cross sections are large to breath close to Headers.
 
image.jpgPpimage.jpg

I have a couple of pics under the car, I'm assuming there is plenty of room for the walkers and doing an H or X pipe?
 
So if I can order the Walker mufflers through Summit, do I order the rest of the system through them as well?
Did Pontiac's original exhaust lay-out include anything else besides the mufflers like resonators?
 
Will cast iron exhaust headers from a 421, 428 or a 455 Poncho - anything with a 2 1/2" exhaust fit my 400 and point in the same direction for duals? I figure a 421 was available for '68 in the Catalinas so wouldn't it stand to reason I can use the 421 -455s as an easy bolt-0n? Should I just consider a good brand pair of headers.
My 428 stand alone is 80 miles away and the one man shop is closed until Corvettes at Carlisle is over so I can't use that.
 
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What would cost more - factory cast 2 1/2" or a pair of best performing for Ponchos headers? Is it like anything else when using headers, you hear the valve train more and the who system is louder?
 
The Very best to use is the special 1965 2+2 421 376 HP Tripower Catalina exhaust Manifolds.
Made like Headers .
Custom bent 2-1/2" system required
 
I've been trying to get this exhaust adventure moving. Nobody has a layout for any Catalina. Summit says call Walker they own Magna Flow. No they don't
Tennico owns Walker, DynaMax and Thrush.
They have a DynaMax Super Turbo or the VT. The VT is a valve that opens when needed.
This cold is kicking my ass, can't think anymore.
 
I've been trying to get this exhaust adventure moving. Nobody has a layout for any Catalina. Summit says call Walker they own Magna Flow. No they don't
Tennico owns Walker, DynaMax and Thrush.
They have a DynaMax Super Turbo or the VT. The VT is a valve that opens when needed.
This cold is kicking my ass, can't think anymore.
Just Rest.
1965 2+2 421 HO Tripower Long branch exhaust manifolds reproduced along with special Oil filter adapter block.
Pricey.. $600-700 buckeroos.

I own them.

Exhsust system on the 1968 Catalina is like my 1963 Grand Prix.
Make it. Fabricate it.
 
Exhsust system on the 1968 Catalina is like my 1963 Grand Prix.
Make it. Fabricate it.

How do I make my own without a mandrel tube bender?
Summit sells the down pipes from the manifold to somewhere around the transmission and a universal X pipe that's it.
 
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