Carb ridged petrol pipe fitting

I am now in position to start installing the fuel tank and piping to the carbs, so couple question from you helpful people

  1. what is the size of copper pipe to run from the fuel tank to the fuel pump and then to the carbs, including what size are the fittings on the the fuel tank outlets

  2. I ordered a flexible steel hose for between the fuel pump and the carbs, but it does not fit, looks like two different sizes and both male fittings, can any body share what they have done for the flexi pipe and recommend fitting sizes etc.

Now living in the US I want to make sure when I order BSP fittings, if they are that, I order the correct ones


The copper pipes on my '38 2.5L SS are 5/16" diameter.
How much of the pipe are you missing?
You know about the reserve fuel valve?

Thanks Rob
You just reminded me about the reserve piping Iintend to plu that line up,fittings are my concern as they are probably british standard pipe fittings, not readaly available in the US

BSPP and BSPT have remained in common use in hydraulics applications in the US.

OK that is good, thanks for that, I will start the search

This is the end fitting for the flexible hose on my 2.5 Liter SS. The thread is about .495" OD so probably 1/2", and my thread gauge measures 24 threads per inch. The olive is a standard 5/16".
AFAIK it should be the same for 2.5 Mark IV.

There is only one flex hose. All other connections are like this,

or like this.

Burlens and others sell these soldered end fittings.

Thanks for the Info I will look at Burlen’s

Vaguely remember comments on here that the pipe diameter on the MkIV was changed to a bigger diameter for the MkV so not sure if there was a starvation problem?

Mark V pipes are 3/8" diameter with a Large Capacity Single SU pump.
Probably due to the 3-1/2 Liter outnumbering the 2-1/2 by a wide margin.