I just recently completed a modification to my 63 DC by installing a bypass filter system. The truck has a 2387 with a full flow system and external cooler. I'm running Castrol Syntec and have 4500 miles on the engine and 2200 miles on the oil. Like most oil, it gets a the byproducts of combustion in it, however with the bypass system I'm experiencing a cleanup of the oil after 120 miles. It's going back to clear... ;-) I'll post some pics soon but basically I have a Baldwin B50 bypass filter on an Empi oil filter mount with an adapter (from 3/4-16 Ford thread to 5/8-20 Bypass thread) and steel braided teflon lines. The AN-4 lines are connected off of a VDO adapter tee block on the oil pressure switch location. The return is in the cover for the fuel pump block off (I'm running electric). This system should theoretically help me get to 20,000 miles between oil changes on synthetic oil. I'll have to change the full flow and bypass filters about every 6,000 miles and add oil as necessary. I plan on changing this Castrol Syntec out in another 4K miles and going with Royal Purple, changing filters of course then I'll see if this stuff really works. Initial costs are about $135 for: the lines (most of the cost), the filter bracket ($15), the threaded adapter ($10), Baldwin Filters (B50s X 2) $8 and the VDO Tee Adapter ($12). With the B50 filters being $4/each this seems to be an economical choice. If I want more filtration Baldwin has a larger version of the B50 with more capacity using the same mounting footprint, the B164 that I may try it if I see the oil get excessively "dirty."