Is my 340 stroked

If you're going to use an aftermarket camshaft, you have to 'match' the rest of your parts to get the right combo. I have a 1972 340 block in my street -strip Duster....(For Sale currently).
It's been bored .040 with 10.1 forged pistons, and has an Eagle 4" steel crank. So total cubic inches is 418". The converter, if using an automatic, is really important. Same with the carb, intake, rear gears...etc.