The original full-flow oil filter canister would not fit in the engine compartment, so a remote filter head is mounted on the rear of the block, above the oil pan. This is a very tight fit and the inner (return) line is quite short. The oil filter gauge mechanical sender is attached to a T fitting on the topy of the filter head (outflow side of filter) and an oil-pressure switch (for the electric chokes) is at the top of the T fitting