It depends on how much money that you are willing to spend.They can be bored .060 and stroked to 4inches and you will now have 440 inches.Add Bob Walla heads,A McQuillian intake,the right cam and a very streetable 550 hp is easily done.And that's not maxed out by any means.Welcome to the zoo by the way.NCPOP I have always been fascinated by that engine design. After doing your engine for your 58 I have always wondered what they were capable of in HP rating.