Thinking out loud..

I wasn't sure if he meant 1500 fwhp or rwhp. If he's hunting 1500rwhp that's around 2k at the flywheel. I don't think anyone has gone that far with a gen III block.

You're right about the heads though. 09+ 5.7 heads are cheap and flow around 400cfm.

Yeah think he is talking FWHP, 1500FWHP should net around 1350RWHP or so.