Topic: Late '67 Mustang 390 Fuel Line

[JIMeast]

I have a late '67390 w/Holley 4V and am trying to find out the diameter for the pump-to-carb fuel line.  I am assuming it is 3/8, but do not know for sure. 

[mikelj5S230]

My 4-27-67 built 390 4V is 3/8.

[Bob Gaines]

I have a late '67390 w/Holley 4V and am trying to find out the diameter for the pump-to-carb fuel line.  I am assuming it is 3/8, but do not know for sure.

67's are typically 5/16 not 3/8. 3/8 is typically 68.

[Bob Gaines]

My 4-27-67 built 390 4V is 3/8.

Mike ,your restored car if it has 3/8's fuel line most likely had the line changed for the better flowing 3/8 line during it's restoration. it is a common practice. Most don't notice. the corresponding fuel pump will have 5/16 inlet too.

[mikelj5S230]

Mike ,your restored car if it has 3/8's fuel line most likely had the line changed for the better flowing 3/8 line during it's restoration. it is a common practice. Most don't notice. the corresponding fuel pump will have 5/16 inlet too.

Thanks Bob!  As expected, you are correct.  I rechecked it with my 5/16th wrench, and sure enough it fits tightly over the line, the 3/8th I tried first has a looser fit I didn't notice at first glance.

[JIMeast]

Thanks for the feedback, for some reason, I have been under the impression for some time that the fuel line from tank to carb went to 3/8 in late '67 for a 390 build.  I saw the word "typically" used in Bob's response.  My car was built June 26th, '67 in SJ.  Just about as late as they come.  Was the line diameter changed over to 3/8 for the '68 model year in 390's?

[Bob Gaines]

Thanks for the feedback, for some reason, I have been under the impression for some time that the fuel line from tank to carb went to 3/8 in late '67 for a 390 build.  I saw the word "typically" used in Bob's response.  My car was built June 26th, '67 in SJ.  Just about as late as they come. Was the line diameter changed over to 3/8 for the '68 model year in 390's?

I have learned to use the would "typically" so as to account for the inevitable anomaly that may happen. I have heard stories over the years of the very late changeover but have never personally seen it or seen any documentation to support it. I suspect like many of these unsupported anomaly stories that the late 67 3/8 changeover is simply a justification for a non stock modification.  I have seen late June 67 cars and all I have examined had 5/16. Not that it isn't in the realm of possibility but unlikely at this point .FYI all of the fuel lines were changed over to 3/8 in 68 from 6cyl to 428CJ.