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72 440 RB mechanical fuel pump outlet thread size?

Ghostrider 67

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Hi. Need some help. I thought the outlet thread size was 1/4" NPT but it is NOT. So, what is it? I need the correct adapter to go in there and the other end be a 6AN flare fitting male end.
 
It is most likely 5/16 female inverted flare. Get a 5/16 tube nut and see if it fits.
 
So far, I have 1/4", 5/16", and 1/8". Does anyone KNOW or are we all just guessing? It's a stock 440 fuel pump from 1972. I guess I'm going to have to pull the mother off and carry it to the freaking hardware store and figure out what fits in the damn thing.

Edit. Thanks everyone. The pumps that Jeg's sells for this motor all have 1/8" NPT listed as the output size. SO, i guess i'll go with that.
 
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The pumps inlet should be a nipple that the hose slides over and is clamped. The outlet should be an inverted female 5/16 flare. not pipe thread. If in fact it is the original pump. Post a picture of the pump.
 
Here it is...

20220719_135647.jpg


20220719_135652.jpg
 
So far, I have 1/4", 5/16", and 1/8". Does anyone KNOW or are we all just guessing? It's a stock 440 fuel pump from 1972. I guess I'm going to have to pull the mother off and carry it to the freaking hardware store and figure out what fits in the damn thing.

Edit. Thanks everyone. The pumps that Jeg's sells for this motor all have 1/8" NPT listed as the output size. SO, i guess i'll go with that.
How can that make any sense? Measure it with dial calipers. The steel line measures 5/16", the nut measures 1/2".
 
So I need to ask for a 5/16 inverted flare to -6AN flared fitting? To get to the 6AN 90* going up to the carb.
Not sure if they make one. I would of bought a new fuel pump with npt threads. Then you can get 1/8 npt to 6 an fittings or 1/4 npt to 6 an depending on which pump you buy. If there is such a fitting it is specialty and I doubt any parts stores will stock it.
 
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