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Discussion Starter #1
I think we can all agree that a 1 1/12" primary, short tube header is fine for a mild 302 (like the one currently in my car), and at higher power levels a 1 5/8" (or bigger) long tube header is the way to go, but where does a tri-y fit? In particular I'm interested in a set of Dougs 660ya headers. They have a 1 5/8" primary, 2" secondary, and 2 1/2" collector. I have a 65 Comet, which is narrower than the early Mustangs, so header figment can be a crap shoot. Right now I've got a pretty tame 302, and have a set of Hedman shorties that weren't made right and have a huge leak on one side. I can get them welded, but if the Dougs can support the stroker I'd like to build in the future, I'll just get a decent set of headers now and be done with it.
 

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Discussion Starter #3
Probably 331 with cam duration around 225ish at 050, ported gt40 intake, Trick Flow 170s. I Dont have specific plans for a stroker just yet, but I'm curious what the above mentioned headers would be capable of supporting. The thing that makes me wonder is the 2-1/2" collector, but is that really a restriction on something that has a 2-1/2" exhaust and will never see open headers?
 

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Probably not..as long as the whole exaust is a good free flowing system.

If you were ever gonna open the headers tho, IMO the 331 is right at the point of starting to give up major power compared to regular headers.

The tri-ys really work well for a small cube engine below 4000ish RPM. (Healthy street engine in the '60s) Exaust flow restricted designs..SBF

I'm sure I'll get blasted here in a minute...Here I stand, shoulders squared....
 

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You will be happy with the Doug's D660YA. They fit perfect. My 306 performs great with them. No ground clearance issues whatsoever. I run a low 8 second 1/8 mile and rev to 6800 rpm. These are a true quality header. Hopefully the last set you'll ever buy for that car if you get the ceramic ones. They ain't cheap though.

Hope this helps
Matt


Sent from AutoGuide.com App
 

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Probably not..as long as the whole exaust is a good free flowing system.

If you were ever gonna open the headers tho, IMO the 331 is right at the point of starting to give up major power compared to regular headers.

The tri-ys really work well for a small cube engine below 4000ish RPM. (Healthy street engine in the '60s) Exaust flow restricted designs..SBF

I'm sure I'll get blasted here in a minute...Here I stand, shoulders squared....
your not getting blasted , your basicly right . for the street.

that type of header can be build for low/mid rpm or mid/ higher rpm ..
I"d say off the shelf are the L/M's to keep the butt dyno happy
 

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I think we can all agree that a 1 1/12" primary, short tube header is fine for a mild 302 (like the one currently in my car), and at higher power levels a 1 5/8" (or bigger) long tube header is the way to go, but where does a tri-y fit? In particular I'm interested in a set of Dougs 660ya headers. They have a 1 5/8" primary, 2" secondary, and 2 1/2" collector. I have a 65 Comet, which is narrower than the early Mustangs, so header figment can be a crap shoot. Right now I've got a pretty tame 302, and have a set of Hedman shorties that weren't made right and have a huge leak on one side. I can get them welded, but if the Dougs can support the stroker I'd like to build in the future, I'll just get a decent set of headers now and be done with it.
A good set of 1 5/8" long tube headers can support 500HP. Dougs tri y headers will make good useable power up to about 5500 RPM after that the long tube headers will perform better. It is tough finding headers that actually fit the Falcons/Comets well. I installed a set of 6901 Hookers and the 6102 Hookers and was not impressed with the fit on my 65 Falcon. The 6901 actually fit better and would require less work to make a proper fit. I am now waiting for my Crites headers and hope to install them next week. Even though the tri y's start to fall off in the higher RPM range they are a quality header that have been proven to fit well in the Falcons/Comets. In my opinion with a mild 331 that you are looking to build, Dougs headers will work well for you. You really should just build a 347 as the cost is the same and it will make more HP and TQ at a lower RPM. There just is not a lot of choices for headers in these cars that actually fit.
 
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