The thing is - almost any of us could be right. It all depends on the dyno and the tune. Push it close to the edge and 430+ rwhp is possible. Set it conservatively, and under 400 rwhp will be the result. I know that on my setup going from 15-18 degrees of timing is worth about 30 rwhp. The closer I got to optimum N/A timing, the lower the gains per degree. At the OP's boost level, pump gas and lack of intercooling, he'll be lucky to get within 10 degrees of optimum timing. I know when I pushed my little Eaton M112, with no charge cooling, overspun and making 8 psi on a 306 I saw ~450 rwhp though an AOD. But that was on the ragged edge (probably a little past it, TBH). The OP has lesser heads and intake than I did on my 306; toss in a reasonable tune, and you're probably looking at the 400-440 range esp considering his trans.