[whizco]

I'm thinking of replacing the stock exhaust manifolds on the 67 vert with either a set of the HiPo Exhaust manifolds or Tri-Y's. But I've heard that even though Tri-Y's are better than stock, for the most part, they haven't lived up to a lot of owner's expectations, and are more troublesome than they're worth

So does anyone have the specs for Stock Vs HiPo Vs Tri-Y ?
I guess I'm looking for the most bang for the buck!

I may even consider a set of shorty headers, but that's seems like a lot of money for such a mediocre performance gain on a mild performance engine.

The 289 4bbl engine once rebuilt will be slightly modified, with some mild performance options, such as cam, lifters, rockers, intake, carb, headwork, ignition, etc. It already has duel exhaust, probably will change the mufflers as well.

 

[Gene_J]

Cheap headers are more trouble than they are worth. If you got those you would be way better off with the HiPo manifolds.

Cheap headers leak, rust, get loose often and make lots of noise. But expect to pay a lot for good headers.

 

[whizco]

Yeah, I've got a set of headers sitting on the shelf for a small block I could use, but I'm wanting to keep the appearance stock somewhat and still be able to breath.... Which brings it to Hipo's or Tri-Y's. The only way I would go with shorties, would be if a set practically fell in my lap.

 

[Guest]

Go with the Hi-Po manifolds. They are solid, easy to install, fit well, and provide some performance gain. Only exception: If you plan to create a 400+ HP street beast.

 

[PonyDoc]

I have a set of tri-y's from Cal Pony Cars that have been on my car for over 10 years and about 170,000 miles. (64 1/2 conv) I just sandblasted them and coated them w/ the Eastwood black paint. I had used the Eastwood silversince they were new, but wanted a change. There was NO rust on them and I found that they fit very well. I can even install them WITH the motor already in the car. I will have to get the hi-po Z-bar, as it rests on the pipe, but still works. I have used the 69 351W manifolds in customers cars where they wanted the hi-po type manifolds but didn't want to spend the big $$. They look a lot like the hi-po's and mine go for $125 blasted and ready to paint. I don't like using the generic headers, as they sometimes have to be tweaked to fit.

 

[mrgem]

Doug:
A year or so ago, DrStang posted the results of comparing his A-code with the stock cast logs, HiPo units, and shorty and long headers.

IIRC, the numbers were like HiPOs = 8% hp gain, shorties = 11% and full length = 16%. Can't remember the exact numbers, but they were something like that. You might try and search for that post.