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Discussion Starter #1
Will there be a noticable performance difference between full length headers and shorty headers on a mildly built 351W?
 

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Yes. Full length headers always flow better than shorties. How mild is your build?
 

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Discussion Starter #3
Yes. Full length headers always flow better than shorties. How mild is your build?
Cam Lift .483 IN/.499 EX, Dur 213 IN/ 219 EX, Trick Flow heads, Performer intake, 600 cfm Holley, .030 over, 9.5 CR, roller rockers, electronic ignition, 4R70W trans.
Is the performance difference noticable at the street level?
 

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First off, what car is this going in? Shorty headers for a Fox-chassis Mustang will not work in our Classic Cats, so I am told. Just go with long tubes meant for your year car, and you'll be better off. OTOH, if somebody does make shorties for your year Cat, it makes for a neater/cleaner installation, provided you get someone to bend you up the proper mid-pipes. Your 'mild' build will not really need full-length headers.

Let me know what cam specs you're running and I can plug those cam ramp events into my computer dyno program. That way we'll know where your powerband is. From there we can figure out what some of your drivetrain choices should be -- converter and rear gear.

Let me put it this way... I'm using shorty headers on my 393W. My build is only 10% more displacement than yours, and I stepped up my cam, intake and carb choice accordingly. My cam choice is not meant for high-rpm operation - the power is all done by 5000rpm, so I really won't see much benefit from running long-tubes.
 

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What shorty headers are you looking at? Since you spent the money for aluminum heads, why would you want to restrict the air flow with the shorties? I just can't see any benefit to other than full length tubes. It sounds like a fun combination though, lots of mid range torque.
 

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Does anybody know of any good reading comparing shorty and long tube headers? I've read conflicting articles concerning the shorties. I've read that they're no better than stock exhaust manifolds which I am inclined to not believe. I've also read that the shorties lose some flow at lower rpms when compared to long tubes but would outflow the long tubes at high rpms. I'm not sure if I believe that or not.
 

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Does anybody know of any good reading comparing shorty and long tube headers?
Try this:
http://www.google.com/search?hl=en&q=short+vs+long+headers+ford

Lots of reading and opinions, some articles also.

I went with the JBA swap shortys on my 351W with the option that I could put the engine in a 65 mustang. Runs good in the cougar, sounds good in the cougar and was REAL easy to install. These are some SWEET headers! Could get more power with long tubes but how often am I really gonna be gutting it out to get the last HP on a street car?

John
 

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My friend Jay Brown did a set of back to back dyno runs comparing several brands of headers and stock exhaust manifolds on a nearly stock 428CJ engine. In the testing he found that there was precious little difference between FPA Tri - Y headers and Hooker 6114 long tube headers.

Both brands of header were worth about 20 - 25 HP over stock manifolds. Approximate horsepower levels were:
Stock manifolds 397 HP
FPA Tri - Y 422 HP
Hooker 6114 420HP
Dyno headers 21/4" primary 425 HP

The Hooker 6114 headers made more average torque and more average horsepower than the FPA headers. The FPA headers made more peak horsepower but would lose in a drag race if all other factors were equal.

Large tube dyno headers (won't fit in any car) were good for another 5 HP and had the best average torque and average horsepoaer.

Conclusion: If your car has mufflers the difference betawwen shorty or tri - Y headers and long tube headers would be even less and probably negligable. You certainly would not notice any difference in driving the car.



Does anybody know of any good reading comparing shorty and long tube headers? I've read conflicting articles concerning the shorties. I've read that they're no better than stock exhaust manifolds which I am inclined to not believe. I've also read that the shorties lose some flow at lower rpms when compared to long tubes but would outflow the long tubes at high rpms. I'm not sure if I believe that or not.
 

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My friend Jay Brown did a set of back to back dyno runs comparing several brands of headers and stock exhaust manifolds on a nearly stock 428CJ engine. In the testing he found that there was precious little difference between FPA Tri - Y headers and Hooker 6114 long tube headers.

Both brands of header were worth about 20 - 25 HP over stock manifolds. Approximate horsepower levels were:
Stock manifolds 397 HP
FPA Tri - Y 422 HP
Hooker 6114 420HP
Dyno headers 21/4" primary 425 HP

The Hooker 6114 headers made more average torque and more average horsepower than the FPA headers. The FPA headers made more peak horsepower but would lose in a drag race if all other factors were equal.

Large tube dyno headers (won't fit in any car) were good for another 5 HP and had the best average torque and average horsepoaer.

Conclusion: If your car has mufflers the difference betawwen shorty or tri - Y headers and long tube headers would be even less and probably negligable. You certainly would not notice any difference in driving the car.
My opinion, full length headers on an FE gives the most dramatic hp/tq improvement than any other modification. Those motors loved to breathe and the manifolds choked them down terribly, even the best "factory iron headers".
A 428 with a .600"/300* solid camshaft and headers=Awesome!
The difference between shorties and full length headers on a mild street car, nill.
 

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FWIW, I'm likely going to try a set of the Hedman shorty headers for the early Mustang / Cougar on the mild 302 I'm building up for the 68. My main consideration is ground clearance. With the amount of lowering on my car, I'd be smashing the collectors on full-length headers all over the place. I may even go with a set of the repro 289 hi-po manifolds, haven't decided for sure yet. Either way, I'll take the potential loss of a few HP compared to full-length, to keep them in one piece.


cheers
Ed N.
 

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Discussion Starter #11
Alot of good info and advise guys. I'd love to have the JBA 1653SJS but $750 is a bit over budget. I have the Hedman 88656 ordered. As mentioned above, the articles I read claimed little difference between shorties and full length. I originally tried the Hedman full length 88666 header but ran into probs with pitman arm interference. Also, I have a 4R70W trans, the collector was too close for comfort the the selctor switch. Here's the real kicker, Summit, Hedman and Trick Flow (Trick Flow twisted Wedge heads) all claim there wil be interference with the plugs by going with the Hedman 88656 shotries. I think there wrong. We'll see this weekend
 

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did the headers interfere with the spark plugs?

I am getting ready to build almost exact motor and need to order the headers. i got same runaround and was hoping to get the ones that you ordered. i hope they fit!!!! Scott
 

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I used shortie headers made for a fox platform mustang on my car, I had to take it to a local shop and have pipes made to fit but, they fit better than the rusty old full lengths I had. My car is a 69 with 351w and a four speed I don't think it is a secret that most full length headers don't really fit this application very well. I didn't do it based on cost I did it based on having something that didn't rub on everything and is still better than a cast iron manifold
 
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