I've always stayed with AC filters. For our '78 that used to be PF25.   I believe that was replaced with PF454, which was a sorter filter.

I now use PF1218,which is the same size as the PF25.

About 50 years ago, when I worked in the car parts industry,  I used to sell Fram filters.  At that time they were considered excellent, but I haven't used them for many years....

I use the AC PF35 because it's the longer filter for the small block when it's used in trucks. I figured it has more filter element in it so it would have less of a pressure drop.

I use the short AC filter. But I’d consider the PF35. Good tip. 

I use the Wix 51061 on my 78. It is the large size like th old AC Delco PF35.

Hi Len!  I've used that  filter before too.

I've actually used NAPA - 1069 in my 1982 which I believe are made by WIX. I've had the car 1994 and never had an issue. I also use their air filters (two on my Crossfire)  Best to all.

Wix makes the Napa Gold filter.  Can't go wrong with either.  Fram standard filters are known to be of cheap quality.  Lots of internet documentation about that.  GM doesn't have engine warranty issues that are strictly AC Delco oil filter related so it's easy to assume that sticking with am OEM filter wouldn't be a problem. 

I agree with Adam's Apple, I use OEM AC/Delco filters on all Chevrolet vehicles.