Inliners International Forums General Discussion Engines 261 Remote oil filter line size

Depends on what type 261 block you are working with. The earlier blocks (and all of the Pontiac 261 blocks, at least as far as I have seen) all use the small id 235 size lines because they are all bypass style motors. The later chevy motors use the larger id lines because they are full flow motors. I under stand that there may be some variations i.e. later motor set up for bypass, but that is the general rule anyhow.

If you use the larger lines on a bypass motor without converting that motor to a full flow, you will bleed too much pressure from the main galley and run the risk of starving the motor and bearings of oil.