cletis wrote: "The 270 came from the factory set up for a full flow filter"
The 270 came from the factory with a bypass filter. The 270 is a full pressure engine and can be converted to a full flow filter with a little help. There is a tech tip somewhere that shows the procedure similar to the way "California Bill" wrote about it in his "GMC Speed Manual". Basically drill a hole in the block, tap and plug.
The Advantage of this set up is that the oil will go through the filter, and "clean" oil will shoot trough the main bearings passages. The way the factory set it up was that clean oil was pulled from the engine, filtered and then essentially returned to the oil pan to mix back with the "dirty" oil.
Interestingly enough I have heard that some of the old timers would drop a role of toilet paper in the filter canister of the bypass filters. never had the balls to try that myself.
