Need big block help.

To keep the budget as reasonable as you can spend only where you have to
to get the engine installed and running.
With the low mileage the engine has on it it should be able to be counted on for many fun miles as is.
The basic have to have items would be engine mounts and headers or manifolds.
You have a few choices on both these items.
The c body spool mount and 73 up v8 k member modification has always seemed to work out the most economical for me. This really only holds true if you can weld or have a buddy that can do the welding for you
Otherwise conversion mounts may be better for you. I always considered them kind of pricey for engine mounts but they are very popular with the majority.
Headers or manifolds is not cheap regardless of which route you take. The best thing to do here is watch the for sale adds and be patient for a rare bargain.
It is likely B-body HP manifolds is the cheapest choice as they can be bought on average for
300. They do fit with some effort.
Used fender well headers come up for sale often but require some big holes cut in your inner fenders to install. They are really a race only part and limit steering travel, tire size and ground clearance.
TriY or TTI headers don't come around used much and wouldn't normally considered
budget parts. These are the best or easiest options though.
Hope you got the transmission with the engine. Big blocks have a different bell housing
bolt pattern than the other engines.
Larger radiator a must. Good used are reasonable.
That engine will make your dart a completely different car.
I personally think the tunnel ram would be better on a higher compression engine
but 440s do run well with them. Never cared for the edelbrock carbs though.