I have built engines before, and I love doing it. This time however I wanted to get professional help doing a stroker, plus I wanted to see what it's like to not spend so much time collecting parts.
I ended up with an engine builder and cam/head pro who are highly recommended, plus they are in the same town. Fordstrokers and Camshaft Innovations have a very good reputation. No one is perfect but they do better at not being salespeople. They will be to the point, honest with horsepower, and prices, plus they are reasonable. Don't waste their time being on the fence about your needs. Go with a real budget in mind, and know the details of your plans. I knew basically what I wanted, and it took very little time to discuss and plan my engine. I had the idea of adding mild boost for this engine, and more for a possible future engine. That was no trouble to deal with for them.
Don't collect a few odd parts, some new, some used, all cheap or deals, and then talk to them about piecing them all together. If you start from scratch, you can buy a whole lot more engine than any crate engine anywhere. The base 347 is $1900, and that includes installation of a camshaft. So if you provide(or buy from cam guy Jay Allen), you can have it all assembled, and shipped to you, done.
The stock block isn't good for more than say 450hp, if you see getting close, then buy an aftermarket block. The Mexican blocks are rare but a little better than stock. I should have asked me about that, evidently they have been finding them, and I think $300 or so would get that. Discuss the compression ratio carefully, for boost it can't be too high. Mine is 9.65:1 for use with mild boost(9psi). With more boost it must be lower, with none you can go over 10:1 easily. Work that out with the builder when selecting parts, Woody there is great, just hard to catch on the phone. Wheen you get serious, go through their websites and contact them there or by email. Registering like a member gets you online chat time etc.