By "fuel rail" you mean the dual feed fuel line ?? Reading back-- i think so.
the dual inlet fuel line--whatever brand--for the 4160 or 4150 carb is PLENTY big for a 225 slant 6.
when i first drilled it out it was as small as 1/4" so i would say thats a big problem...
i bet you a beer thats NOT your issue ,as long as your carb is clean and you have 5 psi fuel pressure at wot , you dont have a fuel issue.
