Build me a 800hp NA 512 b block using pump gas

You have the answer...just read Andy F's book. Better use a girdle and steel billet or aluminum main caps. You would be stretching the stock block without those upgrades.
It's all cubic inches, good rods and pistons and rings, good oiling system, massive roller cam with good springs and retainers, the Best roller rockers, INDY high flowing ported heads, INDY Tall Single Plane Max Wedge, of course, Big dominator or maybe tunnel ram with a couple carbs, MSD 7 Ingnition box, 2 1/8 TTI headers...its all doable....just how much do you want to spend....You could just order the motor from INDY and install it...very simple..and that is what I would do...Its a no brainer if you have the cash and want to spend it on an 800HP motor...And I would also then go with a 4 bolt INDY Aluminum block so you dont have to worry about girdles, etc. Just looked at INDY site....605" Street Master Pump Gas (750HP) but add a 1150 Dominator and a couple of other things to get right at 800HP...that should be fast enuf for even your appetite (with PUMP GAS, low compression motor, not 14-1 etc) and it is $19,450 plus $2240 for the Max Aluminum 4 Bolt Main Block puts you at $21,690 Plus about $1000 for options to take it from 750HP to 800HP plus freight to your shop...there you have it for only about $23,000 and just bolt it into your car...but...better have a really great transmission and converter to hold all that plus a DANA 60 rear end with Moser or Strange Internal and Axles with Spool...plus a compelte 4 Link or Cal Track setup plus good slicks and a tranny brake, plus a great fuel pump and plumbing setup, etc ,etc,,,etc,etc...plus 8.50 certified cage, and all the NHRA required clothing, helmet, etc, etc, plus your NHRA membership and drivers license plus your enclosed trailer..cant let that sit outside..wow...my dream setup...

Thanks for the advice 66 Pro-Street but I have built my own engines since 1974 and this one will be no different. The only difference is this is my first big block Mopar.Yes I have the BRC caps and girdle and a few other parts already gathered up so no worries there. I think the car is more than capable of holding the horsepower as it was purpose built for this. After certification in April I will be making licensing runs hopefully by end of May. If I were to buy a complete engine for that kind of money it would probably be something a little more powerful than 800hp.