Horsepower estimate?

I bought a 1974 Dart Swinger non-running. My son and I spent the last 18 months getting the various parts and missing pieces to get it on the road. We have it running now, and it purrs quiet nicely. Can squeal the tires with half throttle. Here's what I know about it. 360LA rebuilt with a Mopar purple cam, stock heads, RPM Performer intake, Carter AFB 650cfm carb, Holley ceramic header feeding 2 1/2" pipes right out to the back. Tranny is a rebuilt 904. Stock driveshaft and 7 1/4" rear end. Stock steel wheels. Someone asked me what kind of horsepower I'm making. I'm guessing 300, but really I have no clue. What do you fine knowledgeable folks think it's making with that setup? As a bonus, what could I do to wake it up even more? I'm leaning to the old Carter as the weak point but you may have better ideas.

Thanks,

Rob