Holley Oil pan 5 or 6 Qts

[GMJimmy]

I recently bought a Holley 302-1 oil pan and the recommended by Holley dip stick and tube for my LS engine in a 68 C10. I usually fill the filter then put in all but 1 qt., start the engine , check for leaks then sneak up on the final qt. while checking the dip stick. Well the instructions say 6. qts with a filter so I filled the filter and installed it then put in the remaining oil from a 5 qt. container and when I checked it it was full? Holley says 6 qts but....... I called Holley tech and they were baffled but didn't have an explanation. Has anyone here used this oil pan or the 302-2 or 302-3??