Qajj

Upon research to find what size 1st gen's fuel supply lines are, I was finding that 5/16" was the common answer, and I also confirmed this via measuring, so that way I would know which size to get for the hardline to AN fitting. However, once I actually received the fittings, I noticed that they did not fit onto the stock fuel hardlines but did fit onto my Holley 465 CFM carburetor inlet (not sure about the stock Nikki but I still have mine around and could verify if requested). It turns out that the stock fuel supply lines are actually 8mm and NOT 5/16". 5/16" is actually ~7.94mm when converted to metric, so fittings that were precisely machined (such as Earl's in my case) will not fit 8mm hardline. My solution to this was to buy a new hardline in true 5/16" and replace the original 8mm hardline, but a few members of this forum said they were able to 5/16" AN fittings onto their 8mm hardlines. This seems to largely depend on what brand of fitting is purchased and its tolerances. If anyone has converted a 1st gen fuel system to AN, please comment below what fitting(s) you used and also if running new 5/16" hardline was required or not.


Fittings that I purchased from Earl's

Richard Miller

I replaced my fuel lines with 3/8 NiCopp. 6AN from multiple manufacturers but most Beijing from .. sorry Being from Amazon (Evil Energy) . I have not ran fuel through yet though I have ran filtered air through as a stress test to catch leaks. Leaks that seemed to be from my inexperience in installation.

tommyeflight89

iTrader: (4)

So you are going to be running the Holley, what about the fuel pump, have you upgraded that also?

Reason I ask is you might run into an issue with the OEM return line diameter I think all 12A cars were 8mm feed and 6mm return.

I installed an aftermarket fuel pump and could not get my fuel pressure low enough, and had to run a new 3/8" aluminum hardline. To go between the hardline and hose, I installed -6AN tube tube nuts and flare, and then used -6AN to hose barb adaptors.

Not sure the scope of your project and if you will have issues with stock return line diameter, and what about your fuel pressure regulator? I assume your FPR is what connects to the chassis hardlines and then its a straightforward NPT thread (usually) to go to your carb.

Qajj

I'm currently running a MSD 4070M for my fuel pump which has a 6 PSI internal regulator. Due to the style of carb I'm using (Holley 465 CFM) a return line is not necessary so it is capped in the bay at the moment.

Fuel pump