I don't think you'll see much difference between regular LT's and the Tri-Y's.
The bigger difference would be in looking at shorties v. LT's. If im not msitaken, LT's sacrifice a little torque at the expense of higher top end gains, while shorties are just the opposite.

You'll have more options to choose from if you just go Long Tubes, so thats just my 2...

 

tri-ys fo sho need a ps adapter cant remeber if it has any interference with the starter.not sure about the rest of the LTs also there may be a heat issue by the trans pan if I'm not mistaken but I don't know how much heat transfer there is or if it even effect any of the tolerances.

 

I know for fact you need a special bracket with tri-y's with PS but most of the time its either included or can be for only a small charge. As far as the starter or not I've seen some of them listed for differenct applications. As in certain years needed a certain fit if you had an automatic transmission. But tri-y's are a great header. They aren't as big of a fitment pain as LT's and are still a good flowing easy to install TUNED header.

 

I learned the hard way that the tri y's need a bracket for the power steering, you could very easily modify the one you have but, I believe the part number from cjpony is SCB.... but i am not certain

 

Not to derail the conversation but, Is there is difference in how the header reacts to powercoating? White vs Black vs Chrome looking? I was toying with the idea of getting my exhaust coated white like the old 60's race cars.

 

if you got ace welding skills make your own, father did it for our 64 comet, look awesome-
here's an article I have from one of my dad's magazines back from when I was living in
New Zealand, little article about headers, somewhat informative-NZ Hot Rod Magazine, July 1983

 

horsepower tv tested all 3 on the same engine the tri y style made the most hp but it was only like 5hp then the long tube style

 

All this work and money for Headers for 5more HP doesn't seem worth it or I am I wrong on the total HP gain when Headers are add.

 

You have to combine things. If you just throw headers on, you'll have just a small gain. If you up the intake, change the cam and add a good set of headers, you'll probably see a decent gain.

 

how much do you think you'd lose then if you built up an engine and left the original manifolds on??