Transplanting TPI into '55 Chevy-my new fuel tank just has a nipple for attaching the fuel return line. My intent is to run hard line along the frame rails then use braided stainless from rail to the tank. How much pressure is there in the return line...will a high pressure FI hose be ok from the rail to the tank?

Mike

 

I'll take a stab at this.
Theoretically, there should be very little pressure in the return line (it's open-ended in your case), but you have to cover for all conditions.
Suppose the return line got pinched or kinked somehow.
You have to spec your hose for the worst case scenario - full pressure conditions.

 

Correct. The return line should have no pressure beyond the line restriction imparted by the hose and fittings. Most EFI hose is rated to at least 80 PSI working pressure. Return fuel hose can be less. The conversions I've done were fitted with EFI hose on the pressure side and standard fuel hose (not emission hose) on the return.

 

Just a FYI which you may already know. If you are not using an EFI tank with a baffle, count on keeping the tank fairly full to avoid loss of fuel pickup on cornering or hard acceleration.

 

Thanks for the reminder....

Mike