Are 421 or 41 headers better?

Are 421 or 41 headers better?

4-1 Headers However, dyno tests have show that at low RPM there is very little difference in power. The 4-1 headers usually have less back-pressure than the 4-2-1 header and customers have stated their cars seem louder at high RPM with the 4-1 headers.

What is a 421 manifold?

First of all, why does this particular system go by “4-2-1”? The numbers refer to the exhaust pipe layout: Four pipes come off the cylinder head (or additional header), which turns into two pipes, and the system finally ends with one pipe leading to the catalytic converter and muffler.

Do headers make a difference on a stock engine?

Headers are installed because they boost the rate of exhaust flow out of your engine compared to OEM stock exhaust manifolds, which are typically designed to take up as little space as possible.

Why do cars have four exhaust pipes?

Adding a second exhaust system so that each head and exhaust manifold has its own system allows double the exhaust to be forced out of the engine, thus increasing horsepower. Dual exhaust also decreases some of the back pressure that is common with single exhaust systems.

How much hp gain from headers?

So how much hp do long tube headers add? If attached to a stock engine, you can expect about 6-9 hp over a manifold.

How much hp difference between 2 manifolds?

After all of the testing and hedder/manifold swapping and pipe swapping in the 455 test we ultimately saw a 3 hp difference between the 2 sets of manifolds and the shorty hedders. And a mere 5 ft-lb spread in measured peak torque between them (note that actual peak torque production in the engine would be reached at lower than 4,300 rpm).

What is the best exhaust manifold for 389 Tri-Power?

389 Tri-Power Dyno Test With hedders and manifolds in hand, contributors Jim Dietzler, Jim Taylor, and Mark Erney headed over to Bitner Automotive to test the exhaust pieces on the 389 Tri-Power. Here are the results of that dyno test. The Hedman long-tubes performed best followed by the ram-air manifolds, then the logs and the shorties followed.

What size are the bent pipes on the manifolds?

In these pulls the shorty hedders, the RARE manifolds and the Performance Years manifolds all have the 2.5-inch mandrel bent pipes. Perf.

What are the advantages and disadvantages of a long tube header?

Advantages: The long tubes outperformed the shorties and the manifolds in testing on the 389 and the 455. They look very aggressive under the hood and they are lighter than manifolds. Disadvantages: Typical fitment and clearance issues in the engine compartment and with the ground come with the territory with all long-tube headers.