I have a 400 sbc 4 bolt main i want to build into a 406 to put out around 400-500 horse. anyone have any kind of specs. or blueprint i can go off of? I am doing a complete rebuild and am trying to go with my stock 400 heads, my budget limits me to around $1500 so any advice would really help, as far as pistons, rods, crank, cam and lifters and intake. I have a holley 600 carb and edelbrock torker intake. will these be sufficient for a 400-500 horse build?  

Unfortunately $1500 will not get you close to 500 hp.  I also have a 400sbc 4 bolt main and have been doing a lot of research.  The cheapest price tag I can come up with to get close to the 500 hp mark and have the motor still be a good reliable street motor (running on 87 pump gas) is around $3000/$3500.  The machine work to be done on the motor will cost $500 alone (bored .030 over with torque plates, align hone the mains, and zero out the decks....plus hot tank).  Scat makes a fully balanced rotating assembly: crank, rods, pistons, file fit rings, bearings, flexplate, and harmonic balancer that can handle 600 hp for about $1150.  This would be ideal b/c if you are running 500 hp your torque will be in the 520-540 range based on the cam you choose.  I've been considering a balenced rotating assembly by Eagle that can handle 500 hp, $700 thru Summit.  If you went with some inexpensive GM vortec heads the small intake runners would provide good low rpm torque, which is what makes a good street motor, and still make over 400 hp with dished pistons to keep the compression down.   Check out the article titled "The Impersonator" part I and part II on cheyhiperformance.com  it helped me out a lot.