There are also various aftermarket added capacity pans w/pickups...cheap. Look on ebay.
I would be careful about the 70-71 Hemi pan because the sump is moved forward and can hit the K-member. '66-'69 Hemi and '69 440-6 is a good choice.
aftermarket pan another one ONE MORE DEEP PAN oil pickups K member shape is the same so 70-71 pan shouldn't be an issue other than it will be level with the bottom of the K so a skidplate wouldn't be a bad idea .
69 440-6pk used the 402 pan , not the 66-69 Hemi pan which require a skid plate because it peaks past the bottom of the K. The pickup for the 402 is readily available.
Sorry , though you meant well but any deep sump pan that hangs 2-3 inches below the K is a horrible choice for a street cruiser .