Deep sump oil pan

http://www.summitracing.com/parts/mor-20730/overview/make/plymouth/model/duster/year/1974

if you look at this moroso deep sump pan..it says it is 10 inches deep from pan rail....that should give ya an idea...holds 8 qts..

also you might want to look at milodon pans too...give you an idea how deep you need to go to increase the capacity....and if you stay with their depth ...you can use their pickup...

and you want to weld in a baffle to keep the oil in the sump during hard accelerations