You are correct Mike, for a track car the dual breather lines might work better in the "push" (high crankcase pressure/ low vacuum) mode.

Tom Vaught

Thanks Tom, that totally answered my question -- for a totally street driver w/ tripower, i only need stock pcv from valley to intake and ONE valve cover breather, 2 is not always better in my case. Sweet, previous owner had NO breathers but just pcv and didn't understand idea of a "loop" of air....I want/need this rebuild to last, I'm stoked.

I've always been a fan of two breathers, pcv and a puke can in the past on my street car. I had the old Hastings double moly filled 1/16-1/16-1/8 ring's on my first motor and at 7000 it had a little crankcase pressure. On my new build I have a single plazma moly pack, but am still going to run the dual breather, puke can and pcv.........

Anyone know where a flow chart or values/specs for PCV valves can be found?

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If you have the hood clearance you can put a spacer between the carb and the manifold and drill and tap the spacer in the back or front. this would give you pretty good distribution.

For a drag car with no exhaust a header evac system works pretty good if installed correctly. Not as good as a vacuum pump but second best.

I posted a spec sheet for all of the Ford PCV Valves some years ago.

They all were the Shuttle/ Backfire Spring design.

2.5 cfm to .70 cfm for all of the Ford stuff.

Crankcase does not car whose name is on the part.

A company does sell a "bend-over - got your money from your wallet
set-up. Wagner maybe but not sure Over $100

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