Quote:
Originally Posted by rsavage
They are 25% larger so they will flow better.
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It is a 25% larger diameter, but that is not what makes the difference.
If the exit is the largest restriction, the 2" manifolds have a 1 x 1 x pi=3.14 sq inch opening. The 2 1/2" manifolds have a 1.25 x 1.25 x pi=4.9 sq inch opening. That is a 4.9/3.14=1.6 times as much so a 60% increase in area which should have a huge impact on the ability to flow.
My opinion is just about any performance level can benefit with the 'vette manifolds.
On my truck the "butt-o-meter" said they made more low speed torque than the headers they replaced with no loss on the top end. But it has a little cam, 210 @ .050. This is not a fair apples and apples comparison because the headers had 2 1/4" exhaust with some Turbo King mufflers while the manifolds got 2 1/2" pipe with Dynomax Hemi turbos.
Regardless, one of the best mods ever IMO. Good power with low noise and no maintenance.