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- Nov 3, 2003
- Messages
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Where Broncos are concerned, shorty headers are strictly a choice based on the “easier to fit” scenario. That includes the easier to install with a single exhaust system. Or duals, run down just the passenger side.
You don’t choose them for maximum high RPM power, or maximum torque. There are other parameters that handle those, besides short or long.
If done correctly, long tube headers will almost always out perform the shorties. But here again, for the typical Bronco usage, fewer bragging rights is not a performance disadvantage on the trail, on the street, or cruising the mall.
If you’re really cheering for max performance, bigger primaries, longer collectors, and larger diameter, tubing, will almost always get you where you’re going.
With exceptions, of course…
Where you can fit it, a 30 inch collector length is typically the sweet spot for headers. Good luck fitting that in a bronco every time though. Probably can be done, but it ain’t always gonna be easy. Or pretty…
Then again, there are almost always exceptions, of course…
The 30 inch length came, if I’m remembering the length correctly, from multiple episodes of Engine Masters.
For you rheiser, what power level is your 347 intended to reach? What did their dyno sheets show?
Depending upon that answer, you could find anything from 1.5 inch tubes, all the way to 1.75 tubes!
You’ll almost never need a dual 3” exhaust, but dual 2 1/2’s could support pretty much anything you want. And be easier to route through a bronco chassis.
A single 3 inch however, with the right muffler, and the right type of merge, could be the best combination.
For a Bronco anyway…
And, as was mentioned before for the OP, verify that the cylinder heads are not designed for a specific size of flange.
For some heads, an 1.5 inch tube design would be too small. For other heads, a 1.75 would be too big.
What does Blueprint say?
You don’t choose them for maximum high RPM power, or maximum torque. There are other parameters that handle those, besides short or long.
If done correctly, long tube headers will almost always out perform the shorties. But here again, for the typical Bronco usage, fewer bragging rights is not a performance disadvantage on the trail, on the street, or cruising the mall.
If you’re really cheering for max performance, bigger primaries, longer collectors, and larger diameter, tubing, will almost always get you where you’re going.
With exceptions, of course…
Where you can fit it, a 30 inch collector length is typically the sweet spot for headers. Good luck fitting that in a bronco every time though. Probably can be done, but it ain’t always gonna be easy. Or pretty…
Then again, there are almost always exceptions, of course…
The 30 inch length came, if I’m remembering the length correctly, from multiple episodes of Engine Masters.
For you rheiser, what power level is your 347 intended to reach? What did their dyno sheets show?
Depending upon that answer, you could find anything from 1.5 inch tubes, all the way to 1.75 tubes!
You’ll almost never need a dual 3” exhaust, but dual 2 1/2’s could support pretty much anything you want. And be easier to route through a bronco chassis.
A single 3 inch however, with the right muffler, and the right type of merge, could be the best combination.
For a Bronco anyway…
And, as was mentioned before for the OP, verify that the cylinder heads are not designed for a specific size of flange.
For some heads, an 1.5 inch tube design would be too small. For other heads, a 1.75 would be too big.
What does Blueprint say?
