1967 327/300 Fuel Line - Diameter?

[Paul L.]

I am attempting to fab a new gas line, fuel pump to carb. This is not a stock configuration as I have an aftermarket carb. So off-the-shelf is not possible. Two AN adapters will be used. Tubing is apparently measured as to outside diameter (OD). Many suppliers for adapters spoke of -6 AN to SAE 3/8". That seems to be a common size. But the stock lines for my 1967 327/300 seem to have an OD of 5/16". When flared (37*) they are 3/8" on the end. The AN parts are not available in 5/16".

I have two sets of AN tube nuts and collars in the 3/8" size. But the 5/16" tube is loose on the collar. That concerns me. It does snug up when tightened. So is the 5/16" a correct size for my engine? What engine uses 3/8"? I will post a pic.

[Paul L.]

Pic *NM*

[John H.]

Re: 1967 327/300 Fuel Line - Diameter?

Paul -

The pump-to-carb line on a 327/300 is 5/16" O.D.; the main line on the frame is 3/8" O.D.

[Paul L.]

Re: 1967 327/300 Fuel Line - Diameter?

Thanks John. I guess my eyes can still focus correctly. What I am trying to do is replace that SS braided line in the pic with a solid steel line. And the -6 AN connectors from Russell just do not look or fit right with the 5/16" line. Given that the AN 90* adaptor is already on the fuel pump end my next step might be to single-flare a 3/8" steel line (both ends) in a pretty straight run from the pump to the in-line filter (mild curve needed). That will save me making that sharp bend near the pump. In that the braided hose is already oversize (both ID and OD), and the car runs well, adding the 3/8" line should be OK. But I would certainly appreciate comments!

[Paul L.]

AN Adapter - Fuel Pump End *NM*

[John H.]

Re: 1967 327/300 Fuel Line - Diameter?

Paul -

I don't think you're going to find any AN fittings or adapters that will work with 5/16" tubing, from either Aeroquip, Russell, or Earl's, and none of them make any adapters from AN sizes to SAE 45* inverted flare either.

I think your solution will be using 5/16" OEM tubing, and using a Weatherhead brass adapter fitting at your filter inlet - male NPT on the filter side, and 5/16" SAE 45* female inverted flare on the line side. Then you can bend up a 5/16" hard line from the pump to the filter inlet with SAE 45* male inverted flare fittings on each end.