Hi all, I know this is an old subject, but I’m just curious. I'm running an AC 1218 oil filter on my '91 full size Blazer (5.7L). The manual specifies a smaller oil filter. Anyone else using the AC 1218? Of course I prefer the larger filter but I’m not quite sure why GM would recommend a smaller filter. Also, I have the OEM oil cooler if it matters. Any thoughts?