Holley 4150 and sealing fuel lines properly

I spent all week thinking about what the hell is wrong with the new Holley set up . . .
In the meantime decided to get rid of the hard chrome fuel pipes and buy a braided line unit which would not be so rigid and fussy to seal.

A scrounge around the internet forums left me confused as to how to seal the fuel lines properly. There were all sorts of peculiar answers and remedies including using teflon tape on the threads (a total waste of time if you know anything about how they seal), putting little zinc washers into the end of the pipe to squash for a seal to putting little thing fuel resistant O rings in the brass fittings.

All of these "fixes" are supposed to have worked for those who spruik them, but what troubled me is the total lack of reference to anything like them by Holley. I refused to believe the people who make the carbs would not supply a washer/tape/O ring if you needed one to stop leaks. So I had a chat to a racing mechanic who suggested I grease the lines before tightening. "I know" he said, "the fuel will melt the grease, I just have always done it and it always works. I do not know why"

So I had a good think and used the technique to stop the fuel leaks. It worked!
Here's how I stopped the fuel line leaks at the carburettor.

Undo the brass fitting in the carb, put it gently in a vise and then you can screw in the fuel line. Being in the vise you can get a good look at it and be sure it is going in straight. Put a little grease on the thread and on the end of the pipe before you screw it in. I think the grease enables the hard metal edges to slide together tightly without distortion of the metal where they meet.

Once the pipe is tightened nice and straight, you can pull it apart and check to see if you have a nice even score around the seat or if there are breaks. If not happy, just regrease and tighten up again, back it off a tad and rotate the pipe to score a micro lip.

When happy with the connection, undo and refit to the carby. Make sure they are going on straight and don't forget the grease.

I pulled the carb off and checked the seal around the phenolic spacer. It appeared to have leaked so put new gaskets in and tightened it up . . . the book says 5 Ft/Lbs but I reckon that just is not tight enough. So I cranked it by hand till I felt it was tight, in a cross pattern.




After some fiddling it finally started and ran very rich. I leaned up the mixture and got it running quite well. The stang is a new beast with this high breathing, big squirting Holley, it has loads more acceleration and jumps from 70 to 90 MPH in a heartbeat.

Still is a bugger to start when it is cold, backfires and carries on, till it starts and then runs flawlessly. Think I better go have a carby expert look at setting it up using the right gear to get the mixtures right.