help

hello im new here and i want to get the most hp for my money out of a sbc 400 engine.  I've decided to go with a scat rotating assembly kit requiring .30" cylinder bore to 4.65 4" stroke and 6" connecting rods with 9:7:1 compression pistons with all forged components c-moly rings.  I have a garrett 6-71 supercharger already.  I also want to add about 150hr nitrous kit. I want to have at least 750hp at my flywheel. I'm trying to stay in a budget.  I have 4000 left for top end, and valve train I could exceed my budget but not by too much.  I also want to run off pump gas. Is this at all possible (Stay streetable)?  I don't want to put too much in my motor. As i have body, suspension, braking, tranny, and rear end issues to deal with, so some good proven formulas would be quite helpful.  My block has been sonic tested and splayed. Thanks much    

The factory 400 bore is approximately 4.125 inches, a .030 in. overbore would make it 4.155 in. I have no idea where 4.65 in. came from.

A 4 inch stroke is also very difficult to fit into a factory block, even though it can be done it leaves little room for connecting rod length and the ring pack.

Determining what kind of cubic inches you're going to have first would be a good idea before getting into more detail.  

it is 434 cubic inch displacement and 4.65 is a typo its supposed to be 4.165  

Since the cylinder walls on a 400 block are fairly thin to begin with, boring it out to 4.165" is gonna be pushing it for cylinder wall integrity. Before going down this route, defintiely have the machine shop check the thickness of the cylinder walls, and they're overall condition so you'll know if they'll take a big bore like that.  

Horsepower costs  money. I may be a little skeptical about the rotating components depending on what exactly they are (you didn't really specify) since you will be putting a lot of power to them.

Your valvetrain shouldn't be too pricy since your rpm's won't be through the roof but you are going to need to spend $1500+ on a set of "quality" large-port cylinder heads.

Pump fuel will also probably not be possible with forced induction and nitrous oxide being used. It's too much of a risk since with all that oxygen it would be way too easy to disintegrate your engine.

You may also run into a problem with your pre-packacged rotating assembly pistons since you are going to need a large dish to get the static compression down for your power adders. If your stuck with flat tops, which is what I'm assuming is going to happen, you may need to make sacrifices elsewhere such as getting a large-chamber head.  

I have not put the rotating assembly in so should i return it and go with a smaller bore