That low compression ratio is going to hold you back from making 400 HP, you need at least a whole point higher than that. Best way to make 400 HP fairly cheap is buy a used running L31 SBC, throw a decent performance cam in it along with a new timing chain and oil pump. GM sells a Qjet intake manifold with EGR port for Vortec heads. Only tricky thing is installing a in tank fuel pump as L31s do not have provisions for a mechanical pump. Factory Qjet is quite capable of 400 HP while still being streetable.
SBC powered 1987 Regal with TES headers, ZZ4 intake, ZZ4 PROM chip, mini starter, THM2004R, 2500 stall converter, 2040 cam, CCC system, and 3.73 posi rear.
2008 ex NPS P71 Crown Victoria, cop motor, cop shocks, cop brakes, and Jmod.
Never argue with an idiot.
They will just drag you down to their level and beat you with experience.