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Discussion Starter #1
So I'm putting a set of Hooker 2451 headers on my 76 Nova (these headers are made to fit my year model Nova). It has the crankcase evac weld in bungs and check valves on them from where someone welded them in near the transition zone of the headers. The driver side fits fine, the passenger side was hitting the bottom of the firewall. I took the check valve off to see how it would fit but the bung still just barely touches the firewall and will not work. I cut it off and tried seeing where I could possibly re-weld it in but the only possible place would be on the other side of the header but it would be very close to the servo cover on the trans and could probably create issues later when I go to run my transmission lines and I doubt that welding it into the transition zone of the header is recommended, unless it's ok to do that, then I could do that, but what little common sense I have, tells me it wouldn't be the thing to do...

If that's the case, could I run the evac system on just the left side header and just plug/cover my right side header up and run it like that or would I have issues?
 

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Discussion Starter #2
I don't know why I didn't think about it sooner but I guess it will be worth trying to cut the bung at an angle and then see if it will work that way and then I can weld it back in it's original place.
 

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EFI/N2O JUNKIE
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I had to use some steel pipe fittings on the passenger side of our slower car so the check valve would clear the firewall. Driver side was no problem.
 

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Discussion Starter #6
Different question but still related to the thread. Can I run a pair of bullet style, straight through race mufflers with an evac system??? I've seen where people have with no problem, some do have issues and some of the manufacturers that sell the evac kits say not to run it with a muffler. I figured if it's a straight through mini/small bullet muffler, I don't see backpressure being an issue?
 

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Different question but still related to the thread. Can I run a pair of bullet style, straight through race mufflers with an evac system??? I've seen where people have with no problem, some do have issues and some of the manufacturers that sell the evac kits say not to run it with a muffler. I figured if it's a straight through mini/small bullet muffler, I don't see backpressure being an issue?
I use Pypes M-80 mufflers, which are bullet type. My evac works fine.
 

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Evac generally has 1/2" pipe welded at an angle in the header collector. You say bungs, bungs are just a female threaded insert that gets welded in for an O2 sensor and such. A Nova should have a lot more room than my 3rd gen F body. I used short pieces of 1/2 pipe and test fit around the collector for clearance before I drilled the hole. The pipe needs to be at an angle to create the suction to make the evac work.
 

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When I've had clearance problems with pipe and check valve clearing the floor or firewall I mount them on the outer side of the collector. Rocker panel side. Need a little longer hose maybe.
 

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Discussion Starter #10
I found out last Friday when I called Holley/Hooker, that part number 2451 headers fit only 68-74 Nova, not 75-79, even though Jegs and Summit both say 68-79 for the 2451. I ordered the correct pair from them when I called, so the fitment issues should be fine. Will have to buy another evac kit though after I check to make sure these headers fit like they should.

Just wanted to make sure that mufflers and evac systems are compatible. I guess those that have issues with the two being ran together are like eman said, they have to be at an angle, a certain depth into the collector and need to be in the correct range of the collector to work at optimum performance.
 

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If you have the check valves just buy some black iron 1/2" pipe nipples. I cut the ends at and angle and cut a notch in them for suction.
 
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