3/8 inch fuel line

[bn69stang]

When you build or put together a car - muscle car , its easy to overlook fuel line diameter . Project 69 mach 1 m code transformation , no motor or tranny 351 4v is now 428 5 speed car with upgraded fuel line size , thanks to the forum and Barry for the post . I used the stock fuel line not knowing until reading the forum . Part of my car not running to my liking was the line , pick up and delivery to the carb .. Still going to change the cam to a more aggressive profile and install the detroit locker and 3.70 s  but im on the right path now many thanks guyb s ..  Bud

[Falcon67]

It's something to check.  When I first put a 351C 4 V in the Falcon, it would run out of fuel about 5200 at the top of 2nd.  Traced the problem to the pickup tube, where the bend crimp inside the tank left the line no better than 1/4" ID.  Replaced it all with a #8 size full return system and a 140 GPH Mallory pump - no more issues in the last 13 years or so. 

[bn69stang]

Yep  above 5000 was where the symptoms started , im thinking about an electric pump as well also i may have had a kink as well , but did nt even look just replaced it all . A lesson learned for sure , so much work and changing of stuff to go from an m code 351 4v auto manual drum brake car to a  428 5 speed power brake car , the fuel line got over looked ..  Bud

[Mike Caruso]

Oh boy does this one hit home for me.

In 1972 Running a 69 Mustang with a MR 427-454 it only ran 11.87 @ 114.XX and change I was scratching my head. Heck this engine ran 124.xx mph in my 55 Ford @ 3550 lbs back in 1969 with a C6 and a 4:71 gear but only @ 12.13.

My younger brother fixed  Mustang by installing 3/8 lines from modifying the fuel tank pickup all the way to the carb 1-850 added a Holley blue pump removed the old SW A-240 and changed nothing else nothing even spark plug.

First run Bang 11.16 @ 126.xx and change ...... Monster Come Back!!!! LOL

Back in 69 the 55 had a complete 3/8 fuel system how soon I got dumb.

[chris401]

I had similar problems show up in my 65 F250 when I swapped my stock 352 for a modified 390. LMC gas tank had a restriction as well. Had 1/2 installed in tank and I ran 3/8 to rest of truck. Don't know what Carpenter or others offer as high performance car options but I may have been better off ordering a 1 ton gas tank with the larger outlet.

[Mike Caruso]

Hi Chris,
yes it is crazy how some thing so simple will drive you nuts. HA