I got a pan off a Dodge class A chassis that was a front sump.
I believe the pre '72 pickups also used this pan.
The Mopar performance books had some pan dimensions, I'll see if I can find mine.
'72-'93 D and B chassis are rear sump.
All trucks that I've checked hold at least one quart more than the equivalent pass car pan.
Although HP 440s and Hemis might be the exception.
Try leveling the pan and put 6 quarts of water in it, 8 is probably too much!