GMC runs a totally different oil gallery system than Chevy, so ignore the "how to" posts showing full flow conversions on stovebolt engines. It's a shame that most people buy into the myth that an engine needs all the oil filtered all the time. Bypass filters do a much better job of cleaning up the oil, since they take a small volume of the lubricant, run it through a much tighter weave filter media, and actually strain out much finer contaminant particles than a full flow. Anything that passes all the oil needed to lubricate the engine every time it leaves the pump must have a pretty coarse weave media to allow enough volume to keep the engine lubricated. Ideally, an engine should have two filters- - - -a full flow to strain out the "rocks, marbles, and bowling balls" that can damage bearings- - - - -and a bypass filter to catch the stuff that goes through the full flow setup.
Jerry
