Anyone know what size fuel line a slant six car is vs. a V8 car? Also, when you go to a bigger diameter line, do you need to change the sender or can the larger line be plumbed through the stocker and into the tank?
Most all are 5/16 line and it is fine. It is really only long hard pulls like a long freeway pull in elevation, ar a drag car, circle track car with 400+ HP that this is an issue, but as Moper said an electric pump will step up a 5/16 to be O in most cases. U used to see many motor home with 413 wedges, and 427 tall blocks running 1/2" line, but they had 30-50 distances to pull the fuel from and multiple tanks too.
Anyway, yes if you go 3/8 there is a 3/8 sending unit to match. Most 340 cars and up all had 3/8 tube. But I have seen even a 383 cornet with a 5/16 line before.
Hope that helps some?
General rule: If in doubt, install a fuel pressure gauge, stick the car on a chasis dyno and nail at full load at 60MPH wheel speed to see if under a load for more than 1 minute the pressure starts to drop, or if you can safely rig the lines up drive with a buddy and have the fuel gauge mouted wher you can see it when you drive under a full load.
