I've always used the longer AC Delco PF-52 filters. They have the same pattern as the PF-47 but have more filter medium. I believe that they are directly interchangeable. It should be noted that not all oil filters are alike. Some brands use longer more dense filter mediums. I read an article a while back and it gave some good info; [url] http://www.austincc.edu/wkibbe/oilfilterstudy.htm
------------------ " THE BLACK PARALYZER"
-87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
[This message has been edited by Dennis LaGrua (edited 05-23-2015).]