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.Yes. Full length headers always flow better than shorties. How mild is your build?
Try this:Does anybody know of any good reading comparing shorty and long tube headers?
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.
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".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.