Kevin, are you going to build the engine or are you looking to buy the engine ready to rock?
Stock pulls ( engines pulled from cars and trucks ) can be had for $100.
With crating and shipping, you could have a basic engine at your door for maybe $700.
Share with us a bit more of your plan and what you want to do so we can steer you in a completely different direction.
I have a 360 FE you can bore to the 406 neighborhood for $100.