That's about what my 408 did. But I have hydraulic cam (248/254) and 1.6 ratio arms, .600 lift. Compression is 10.2:1 ported Eddy heads. M1 intake, but no spacer, same carb. All in all, very similar builds except the actual heads. My heads flowed 284cfm. Do you know what yours flowed? I could have pushed my compression higher to get more out of my aluminum heads, but I didn't. My best hp was at 5800 and best tq was at 4700 - pretty much the same as yours... built for the street.

You probably spent less than me, so you should feel good!