If it makes 300 HP and right now I think that that's an unknown at this time, I see no reason to get anything other than a stock converter. If it's a non lockup transmission I'd go for a common 225/318 converter with the High Stall decal on it. Check with your local Trans-Star dealer. I believe the part number is CR8H. Make sure you know if the engine is internally or externally balanced before you get any converter. If you really want to get a high stall converter, send me a pm with your home email, and I'll send you the specification sheet the High Stall company a worked for used, when a customer wanted to order a high stall. The cam shaft maker, gives you the stall they recommend for the cam that's in your engine.
Anything higher than 22-2300 RPM for this combination would be a waste of money in my opinion. If you talk to a converter builder that is interested in how his product works after the sale, most will tell you for your typical street driven vehicle, unless it's making a lot of HP, 2500 rpm is more than enough. Match the converter to your engine, rear axle ratio, and tire size. What works for some, may NOT WORK for you.My .02 worth.