Originally Posted by cudaman1969
Originally Posted by ek3
Originally Posted by AndyF
Originally Posted by GODSCOUNTRY340
Nick's Garage just dyno tested a 440 using factory HP exhaust manifolds, max wedge manifolds and headers.
Results:
HP manifolds---- 375 horsepower------ torque- 389
Max Wedge------ 410 HP ----------------- torque-446
Headers ---------- 419 HP ----------------- torque-463
The headers (1 7/8" tubes) increased 44 horsepower. Back in the day everybody claimed they only gave you 15 more horses.


All depends on the combination. Those dyno tests can be "rigged" by changing the camshaft. The results also will change a lot depending on the muffler and tailpipes that are used.
iagree <---> this is where it is...... the correct cam and combo will help overcome the lack in exhaust efficiency . an effective cam would pick up the power on manifolds and there would be little if any from the addition of headers.......

you’re both missing the point, it wasn’t an all out dyno session of many combination of parts, just three different exhaust types and how they worked on THAT engine. Heck he could’ve put Indy heads, roller cams, you name it, the purpose wasn’t for extracting every bit of HP, just what if. Take what he did and go have a coffee break. Sheesh


We're not missing the point, we know what the point is since we've done it ourselves many times. I can do a dyno test just like that and have very little difference between HP manifolds and headers. I can also run a dyno test where there is a big difference between manifolds and headers. The test itself is kind of meaningless since it can easily be rigged to provide a wide range of answers. I can do the same thing with rocker arm ratios. I can "prove" that rocker arm ratio doesn't matter or I can "prove" that it matters a lot. All I have to do is use a different camshaft. And if I don't tell anyone what cam is in the motor then most guys won't know the difference. They'll just accept what the magazine article says as fact.