You can cut out the Durango tank pump mount and bolt it to the RC tank. The depth of the Dakota pumps I've had hands on have a little room to change the depth, and I think (famous last words) that the depth of the RC tank is pretty close to that of the Dakota tank I was in (at the pump part of the tank).

I pulled two pics and attached them, they're from this build thread on RCC: (reply number 533)
https://ramchargercentral.com/mopar-trucks/big-mack-(-here's-the-beef-)/msg2972257/#msg29722577

-Ben