Question about headers

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bucket

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Headers are a nice upgrade, but do buy ones with a 3/8 thick mount flange. I have them on my 82 C20 454, I ordered for direct fitment on my truck & they slide right in from underside with no issues. I also ordered better flange gaskets that I’ve had zero leaks from, also had muffler shop install v-band clamps on my collectors with zero leaks!

Those v-band flanges are a nice upgrade!
 

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You might want to consider ram horn exhaust manifolds. The reading I have done point to that they are pretty much the same flow as headers without the problems.
The 2.5 inch rams horns are similar to headers in lower horsepower stuff. Unfortunately those are Corvette and straight flange instead of angled,like you need on a truck.And those aren't 2 inch. I would be really interested to see if lt1 roadmaster/Impala manifolds would work on a Square. Hey @Catbox is this first screenshot you?
 

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75gmck25

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I’ve alway been interested in whether the old style (straight down outlet) 2 1/2” rams horn manifold can be used on a squarebody without doing a lot of cutting or re-engineering to get them to fit.
They have a good reputation for flow, and there are both original and aftermarket versions still available for a reasonable price ($180-$200).

IIRC, Hooker also sells an iron exhaust manifold that has a 2 1/2” outlet, but I don’t know anything about the design or flow.
 

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The 2.5 inch rams horns are similar to headers in lower horsepower stuff. Unfortunately those are Corvette and straight flange instead of angled,like you need on a truck.And those aren't 2 inch. I would be really interested to see if lt1 roadmaster/Impala manifolds would work on a Square. Hey @Catbox is this first screenshot you?
That is not a post by me.
Strange as I have been online with the "Catbox" handle since 2005.
I always find it weird when that name is already taken on a forum.
 

MikeB

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I’ve always been interested in whether the old style (straight down outlet) 2 1/2” rams horn manifold can be used on a squarebody without doing a lot of cutting or re-engineering to get them to fit.
I tried a pair of aftermarket 2.5" rams horns that dumped straight down. I couldn't see any way to make them clear the drivers side motor mount. However I did see a photo where somebody did it using a very tight pipe bend and some grinding on the manifold flange and/or the motor mount clam shell. The 2" rams horns are smaller in that area, so might work w/o using a very tight bend. But I doubt they flow any better than these that I mentioned earlier. https://www.gmsquarebody.com/attachments/1698077759431-jpeg.325061/

I just now remembered these were listed for 96-up trucks with Vortec heads. Those engines had 255 net horsepower, which would probably equate to at least 300 gross hp at the flywheel, which is how engines were rated until the early 1970s. Stands to reason they would have been somewhat improved over the square body 350 manifolds.
 

Rick R

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Some great arguments on both sides and lots of good information. I chose the Hooker manifolds and so far I am very pleased. My 350, .030 over, w/a 327 cam and Edlebrock manifold and carb. Uncapped it sounds so sweet. I love the fit and have fit my a/c comp. I haven’t driven it yet but will complete my exhaust after I burn the rear tires, then switch the front to back and get rid of the old rubber. And best of all I don’t have to retighten header bolts, ever again.
Best of luck w your decision making.

Old age and treachery will overcome youth and skill.
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