Some c bodies used the 5 qt. It almost looked like the 6 qt. So there is a few designs in the pan shape that add to the capacity. Certain year models had specific part numbers for the dipstick and where it mounted to. If you buy an aftermarket dip stick, a couple of things need to be considered.
Like how deep the shank of the tube goes into the block insert area, the length of the shank to the stop on the tube insert and the placement of the stop at the handle. Even some small blocks have this problem.
On a 402, you install the pan, with the windage tray and the dipstick. Then fill with 4 quarts and check or make your own line on the stick.
If you are useing an HV pump. It will have a tendency to suck the pan dry depending on all the clearance issues in your engine build. High rpm's and a stock pump with the engine all in spec makes for good flow.
A good example is with...SLEEPYCHALLENGER"S 70 r/t challenger. He has a numbers 383 engine, with stock 402 pan and runs his car close to 6k alot
And he doesn't have an issue. My car had an HV pump,with a standard crank and a bit more clearance, so at 6500 and in 3rd gear, It would use all the oil in the pan if I stayed into it in forth at a high speed for any long term driving. I put the hemi/6pk pan on and have no more issues.
If you ran 6 quarts in your 402 pan then the crank was throwing extra oil all over everything and trying to come up on the back rear cylinder walls on accelerating and front on decelerating. Also can cause oil plug fouling and excessive blow by through the covers.
