Hose inlet for Barr manifold

girraf

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I?m swapping in some brand new Barr manifolds on my 350 this winter but they?re configured a little different than the old manifold. The old one had a hose barb-like fitting cast into the manifold that the water inlet hose attached to. The new one has a 1/2? threaded hole on both ends. In one end goes the plug in the attached photo, in the other, I presume I need a 1/2? male thread x 1? hose barb brass fitting to make it all work ( inlet water hose is 1?). I?m finding this difficult to source. Best I could find was a 3/4? male thread to 1? hose barb. I suppose I could put in a 3/4? x 1/2? reducer but now we?re talking like $20 just in fittings. Also, does brass need Teflon tape when threaded into cast iron?
 

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alldodge

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Pipe threads are a bit different and use the inside hole as the size instead of the outside thread.

Your plug looks more like a 3/8 NPT, so the outside thread would be 0.675 OD.

If your manifolds are the dry type, then you will need NPT to barb male fitting. I would guess male 3/8 NPT to 1/2 barbed fitting.

Which manifolds did you buy and have pics?
 

girraf

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Here are a few more pictures. The calipers are measuring the max diameter outside the threads and then the barrel of the plug between the threads. Only reason I thought it was 1/2”? MIP is because I was in the ace hardware today and the threads on the plugs matched best with that size. I know pipe sizing can be finicky which is partly when I’m looking for some help. The manifold is symmetrical for left or right hand installation so the plug installs as appropriate and the water hookup goes on the “other” end. I ordered the Barr manifold kit for Volvo Penta 5.0/5.7L with 4”? exhaust.
 

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alldodge

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To me that is 3/8 NPT thread and the hole on the end is the casting, which can be plugged if there is a hole on the bottom, but in your case this is where water is feed.

fetch


What year is the motor?
 

Scott Danforth

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1/2" NPT. Bronze fittings for 1/2npt to 3/4 hose are common, 1/2npt to 1" hose are available, just not as common

$20 worth of fittings is cheap If they were stainless, you would be spending closer to $60
 

girraf

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I was thinking that all Barr Manifolds might come this way and that there would be other folks who already solved this problem. Maybe my water inlet hoses are a little bigger than normal at 1?. The engine is a new long block 5.7L as of a few years ago with all the OEM accesories(intake exhaust alternator per steering pump etc.) the previous owner installed but the original power was a charcoal series 5.0L GL-PBYC from 1998.
 

Lou C

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I just changed to the Barrs on my '88 OMC and used the standard OMC 90* bronze fitting with a bit of Permatex Aviation on the threads, same with the rear fitting that I use for the drain. The nipple end fits a 3/4" hose. You can use a straight or a 90* fitting either will work....you can see it in this pic....
 

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