Anybody using the R5/P7 for racing?

I've been doing some research for my next build. I'm not up to date on the Mopar stuff. I'm at the planning stages right now. I've been looking at the R5/P7 combo. So far it seems like a pretty good combo. Anybody running this combo for a drag race application. I finally bought a Mopar and now I need a power plant. I want to build a 358ci engine and I only have to weigh 2900lbs. Any idea how much HP you can get out of it? Any input would be great.

Thanks Brian

I have a complete set of P7 heads if your interested.