This threads a little off track...lol
I've built these combos before: 438, 451, 470, & 496 B wedges; 505, 512" RB wedges using my own sourcing for parts, and kits from 440 Source and Muscle Motors. There are many variables to these choices and a lot of possibilities and paths to the same goal. So here's my take:
1. The heads you have will work for any factory displacement, and some of the smaller stroker packages. To greatly simplify things try looking at it this way - a 383 to 496 is a jump in displacement of about 33%. A factory head flows about 220cfm. So you need 33% more flow to retain the performance potential of the new size. That means a 496 needs about 300cfm of intake port flow. You need 33% more carb, and 33% more cam. So the heads you have will work for 438, or 451" packages. That being said - the best packages for pump fuel rely on exploiting modern theory using properties of squish and tumble - otherwise known as quench. An open chambered head needs a lot of work to work on a quench-built engine. IMO it's more important to build for quench than to use heads you have.
2. Longer, non-factory stroke engines do wear out faster. But it's not the bores that wear. The pistons are much shorter. That means there is much less surface area on the skirts to deal with the added side-loading. It also means less support to maintain the rings' relationship to the cylinder wall especially at TDC, where holding pressure is critical. So the rings wear faster, and the pistons wear. The last 496 B wedge I did is closing on 17K of hard, abusive miles. It is starting to show signs of wear (oil use) although no other issues are present. I'd expect something of that type to last 20-30K. The taller the piston, the longer the life. A 438 or 451 will last like any factory displacement.
3. Cost factor is the same as the rest... I live in the most expensive state in the union and use the best shop I could find. I don't ask how much. I say "I want this done". So these are pretty "unique to me" costs. A 1hp/inch engine (say, 380-400hp 383) will cost around $16/hp. A 1.2hp/inch engine (say, 460hp 383) will cost about $16.30/hp. In terms of factory stroke packages the bigger the engine the less dollars per hp need to be spent to get the bigger power number. Any non-factory stroke will cost more. How much more depends on a lot, but again simple math based on the 383 would be a 1.2hp/inch 496 should make about 590hp, and would cost around $16.90/hp or around $9900. A 1hp/inch 496 will cost slightly less. Performing strokers are not cheap. If you're worried about the cost, you're much better served building the 440 as a 440. But for a modern build, using middle of the road parts, and consisting of everything new but the block, crank, and rods you're going to spend $6500+.
4. Exhaust manifolds are a hinderance, but not a huge one. What their use means is that the camshaft has to be a custom unit by a designer that specializes in their usage. That 496 one stock appearing at carlisle and in that form also put 490hp to the rear wheels. With headers and a larger carb it makes 530 to the tire. Same camshaft. A custom solid flat tappet unit by Porter Racing Heads in VT.
So you need to determine where you are money wise, and where you want to be power wise, then talk to your machinist to formulate a package that will get you there.