little 'ol 273

I have a '67 Barracuda Form S notchback with the stock 273 Commando, Ed. Performer intake/ Holley 570 St. Avenger, 8 3/4, 3.23, dual exhaust. Just got the go ahead from the boss (wife) to get the engine rebuilt. Anyone have advice on what I could do to add performance? Maybe get up to around 300 hp. Please, don't tell me to get a 360 - I went to a MOPAR guy out here not too long ago, he told me to ditch my engine and couldn't offer any other advice. I would like to keep what I got. Any advice from you guys would be much appreciated..... (I'm pretty new to this stuff, so go easy on me)