Depending on how heavy that plane is when it's ready to fly......I would bet that when completed it will be heavier than the manufactures listed weight. I would put a larger engine in it if I owned it. Weight and wing loading are the things you must consider. The lower the wing loading the less thrust you will need to keep it in the air. Up the weight and the wing loading and you will need a good bit more motor to keep it in the sky. Caution though.....alot of these ARF's are built from really lite poor quality wood. Despite the size if you put a larger power plant in one that has not been strengthened in several area....it might shake apart. I had a friend who flew a 40 sized ARF for the first time with a 40 engine in it. Well half way down the runway the firewall and motor fell out. Let severl other guys at your club look it over and get a balanced recommendation on what to power it with. If I had it in my hand I could give you a good suggestion...........
Remember to...it's a "SCALE" old time racer probably more for looks than speed. Neet lookin plane though....I have thought about getting one similar to it
If you really want to go fast look into a purpose built speed plane....Viper, Q-500, Patriot, some Warbirds, and PropJets.