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I'm putting the manifolds back on my rebuilt 1967 HiPO 289, and I'm debating whether to put the HiPO exhaust manifolds back on or install headers.

This engine is Paxton blown, and I'm told that it's best to have the most free flowing exhaust as possible with a blower.

I understand that the HiPO exhaust manifolds are more free flowing than the regular 289 manifolds, and would not cause the issues associated with mechanical interference with the power steering unit, and heat on the PS hoses, etc.

I've read most of the posts on the subject, but am still a bit confused....

Is there a hassle-free way to install headers on a 67 GT350 ?

Is there a significant difference in performance between headers and the HiPO exhaust manifolds ?

I am concerned about originality, but not at the cost of performance and maintenance on the blower (assuming more back pressure causes more maintenance on the blower).

Thanks for your comments, opinions, and experiences.

wjj
 

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I'd go headers.....I've seen the fit and finish on a set of smallblock dynomax headers, and theyd probably be the ones I'd use.
 

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Regardless if they are HIPO, manifolds can't compare to headers in flow and performance. I'd get a set of Doug's Tri-Y's for your car. Wasn't that an option on Shelby's anyway? /forums/images/icons/smile.gif Free flowing exhaust was one of the most notable bolt ons I've done to my car. However, you're going to have to debate about the originality issue yourself. I don't know if you're building a show only car, or a fun weekend cruiser that will see the occasional show. If the latter is the case, personally I'd buy some headers. I like my Heddman Elite headers, but for your app I'd look at the Tri-Ys or some MAC Headers. They make some for classics, but expect them to be on backorder. All MAC headers are coated too. You'll definitely want coated headers, or you're throwing your money away.

Oh, and does the Shelby project mean the S-code will be for sale soon? /forums/images/icons/wink.gif I wouldn't mind selling my vert for yours! /forums/images/icons/smile.gif
 

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I'd add the headers....If you feel burdened to keep it period original you can always add some Tri-Ys. If you want them to stay looking good, go with a set of ceramic coated ones. Supercharged ! Sounds like a lot of fun ! Dickson
 

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The only issue I have with headers is that the power steering slave cylinder must(?) be lowered with a special bracket.

(IMO) The steering just isn't the same after the modification.

Headers will free up some mid-hi RPM HP, the engine will rev easier.
Plus headers move you higher on the "Cool" scale. /forums/images/icons/wink.gif
 

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Here a nickel from a 67 Shelby owner.
If I go concours Shelby, I'll do the hi-po.
For a street driven Shelby, Tri-Y.

However, the power steering drop-down bracket has been known to come loose and on a friend's GT350 the captives in the frame came loose and he had the bracket welded to the frame. Ugh.

Now on to yours. Because the drop-down stuff is, in my opinion, crap, have you considered a set of shorties?
They make em for 5.0 conversions in the early cars and you get most of the benefits of the long ones. Ya, you gotta loose something, but anything is better than PS drop-downs and scrapping the collectors on speed bumps.

BossBill
67 GT350
 
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