I always wondered if the PCV that I got on my 261 is messing with the fuel/air ratio (and hurting mileage), and if I should go back to the road draft tube.

From my understanding of a PCV system - and please correct me if I'm wrong - the lower the manifold vacuum, the more additional air got sucked though the crank case into the intake.
So it does pretty much nothing at idle, a bit at cruising and a lot at acceleration/WOT.

So I guess at high rpm and when I floor it, the mixture get's leaned out, which doesn't sound good to me. Am I missing something?

Last edited by Stovebold6; 10/21/2022 6:32 PM.