Her68His69,
I hope this info is helpful in your search, but I believe the screw-on oil filters '68 and up should "screw on" between the 230/250 sixes and the small block/big blocks - only difference is lengths, drainback valve, filtering, etc, which is important too. When I was digging up the info on that old 230 I have from my first '69 Camaro, I noticed it still has a Fram PH30 that I must've put on over 35 years ago. And the PH30 lists for the small block Chevys for some applications. And I have big blocks/small blocks with the same filters - used to use AC Delco PF 35 (may be an old part# now) and now use mainly K&N. Small blocks and big blocks have the filter vertical of course and the inline 6 sits at a bit of an angle. But it may be easier to find a good filter that fits a 350 or 454 with the drainback valve (if that's what you want - I prefer one, don't think it hurts anything to have it), it should fit your inline 6. Of course look at the length dimensions and make sure no interference or whatever, and check whatever other criteria are important to you. So if I'm not right about this, please someone correct me, but I believe the inline 6/SBC/BBC all have same thread and filter base diameter. Might be easier to find one that will work for you knowing that.
