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Discussion Starter · #1 ·
What would be wrong with making a new valley cover (LS engine) from 1/4" aluminum and fitting two nipples, one in front and one in rear, and then plumb into header collectors, instead of cutting valve covers, could plug the small nipples in valve covers or, could also plumb valve cover nipples into the hose going from valley cover to headers, good idea or not ? This would be on an alcohol race only engine.
 

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Header evacuation kits use oil separators on each valve cover. These parts are actually from a Chrysler engine produced in the 1970's or early 80's. These separators are necessary to keep the evacuation system from pulling oil out of the engine . . . . . .
 

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Last time I measured the vacuum on a bbc evac system I installed using a kit was only 3 inches of vacuum being pulled at peak rpm this was on an 11 second bbc car with open headers, i never did it again, figured the 3 inches of vacuum wasn't worth anything for power, didn't even notice any time change in the car.

I just run quality breathers on the valve covers since that test.

Money better spent on some header extensions, bbc's and small blocks seem to be around the 18" long extension, improve low end improving 60ft and reducing e.t. over all.

Best off spending time and money on a vacuum pump to get any true gains if your interested still in the evac route.


Hope this helps.
 

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Discussion Starter · #5 ·
Thanks for the replies fellas, was just thinking out loud, trying to keep it simple, a vacuum pump would probably be better but then there is wiring and the such, the pump, catch can, a header system would be simple, I guess its going to depend on which valve covers I use, fab or cast.
 

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Try it, you won't be out much $ or effort, and see what it pulls. The valve cover breathers are '80s Mopar, the check valves are on a lot of different vehicles (i think the ones I have 'fit' an early '90s Jeep?), and a cheap 6" long 3/4" pipe thread nipple from Lowe's. Never measured the vacuum on mine, but the main reason I put it on there is to pull condensation out of the valve covers. Here in the south, if it sits for a week or so condensation builds up big time in the valve covers. Also the evac does pull more if you have collector extensions but it's not going to be nearly as good or expensive as a vacuum pump.
 
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