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LS Swap Vacuum Questions

Old 03-26-2017, 03:38 PM
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Default LS Swap Vacuum Questions

I am finishing up my LS Swap into my 69 camaro. We were able to start the car last night, but I have a couple vacuum questions. Back ground is a 6.0 liter with ls3 heads and ls3 intake. I am using truck LS valve covers. Questions -

I have 2 openings on the intake behind the TB, do I plug and if not where do they go?
the PVC on drivers side cover back does it go to one of those ports? Could I just put a breather there?
Lastly, the port on drivers side behind TB, what do I put there?

Thanks in advance.
Old 03-26-2017, 08:52 PM
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The driver side port goes to a vacuum source, stock it goes to the port on the top of intake, kinda in the middle.

Im only aware of 1 port on the driver side intake and its the fresh air side of the PCV. Some intakes had the port and some throttle bodies had it, you can put them together and end up with 2 fresh air ports for the pcv. If thsts the case just block 1 and run a line from the other to the pass side valve cover port.

It will be alot easier to tell what youre tslking about if you post pics
Old 03-27-2017, 08:30 AM
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I think some of the confusion is because you are using a ls3 manifold with truck everything else. On an ls3 the driver's side valve cover nipple is capped. The nipple on the intake on the passenger side behind the throttle body connects to the nipple on the valley cover with a small "U" shaped hose. The nipple on the driver's side connects to the EVAP purge valve if you have one. If you don't have the valley cover with the nipple on it, run a hose from the passenger side nipple behind the throttle body to the nipple on the driver's side valve cover. The fitting on the passenger side valve cover at the front gets plumbed into the intake tube between the MAF and the throttle body. If you don't have an EVAP system hooked up you can cap the nipple behind the throttle body on the driver's side. If this isn't how yours is set up post a pic so we can see what all different parts you're working with.
Old 03-27-2017, 10:11 AM
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PDSQ98GT/LSXFord - thanks for the explanation. attached is an image of what i was talking about. I didnt plan on using the EVap system. I have a nipple on the passenger valve cover that i ran to the top of the TB. then on drivers side valve cover I have the hole for the PVC. I do not have a nipple on the valley cover.
Old 03-27-2017, 10:33 AM
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You have two options, either take off the little hose circled in yellow and run an oil resistant hose to the passenger valve cover. Or cap the passenger valve cover and get the ls3 valley cover and use that little "U" shaped hose. Just cap the EVAP nipple either way.
<a href="http://s471.photobucket.com/user/pdsq98gt/media/Mobile%20Uploads/A21BBAAB-4555-4DB1-AC63-AACB07ECB04B.jpg.html" target="_blank"><img src="http://i471.photobucket.com/albums/rr78/pdsq98gt/Mobile%20Uploads/A21BBAAB-4555-4DB1-AC63-AACB07ECB04B.jpg" border="0" alt=" photo A21BBAAB-4555-4DB1-AC63-AACB07ECB04B.jpg"></a>
%5BURL=http://s471.photobucket.com/user/pdsq98gt/media/Mobile%20Uploads/A21BBAAB-4555-4DB1-AC63-AACB07ECB04B.jpg.html%5D%5BIMG%5Dhttp://i471.photobucket.com/albums/rr78/pdsq98gt/Mobile%20Uploads/A21BBAAB-4555-4DB1-AC63-AACB07ECB04B.jpg%5B/IMG%5D%5B/URL%5D
Old 03-27-2017, 11:06 AM
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Thanks for explaining. Really appreciate it.


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