What is the evidence for this? What is a "base?"
Agreed. OP, you should visit your local scrapyard and look at the engines and transmissions available, ask for some quotes.
Pretty much all of the engines you'll find are used scrap with unknown history, and may not develop their factory rated crank horsepower figures without thorough repair and maintenance.
What is the condition of your Potohar's drivetrain? If you end up changing the front and rear ends, the transfer case, the transmission, and the drivetrain, you're only retaining the chassis. Your build may exceed your budget.
Let us know where you're located, and some members can give you insight into the estimated costs in your local market.