which engine to go with

[Ackattack]

I've been on the fence, playing scenario after scenario on what engine to use for my pickup project.

First, the goal: 400RWHP; must be fuel injected!
Second, auto tranny (for bracket racing)

Currently: stock TPI 350 with headers, based on mph making about 250 RWHP....don't know how many miles are on it. I also have a 700r4 behind it that ellis rebuilt about 3000 miles ago.

So here are the options:

1) N/A TPI 355. Basic rebuild with possible new crank and rods if needed. Obviously new pistons. I did some researching on this earlier and would use the new Bowtie Vortec heads and Holley Stealt ram intake and a big cam (can't remember the specs right now)
Pros: Would be fun to build and I should be able to use the current transmission
Cons: The cam selection necessary to get 400RWHP may really make driveability suffer (though not a daily driver by any means). It would probably also take a lot of programming, which I'd have to buy. Also, it wouldn't be cheap

2)N20 TPI 350. Freshened up, probably still run different heads and maybe new intake and a slightly larger cam.
Pros:Cheaper than going N/A and use current tranny, and driveabilty should be better
Cons: Without a full rebuild on a tired engine I think this would be a ticking time bomb. Running nitrous safely still costs a little money, plus I'm not a big fan of nitrous.

3)N/A 6.0L Probably run it as recieved, decent sized cam and headers and maybe some slightly ported heads. Would also run a 4L60E tranny.
Pros: Its a gen III engine! Would probably be a lot more reliable, I'm pretty familiar with these engines, I have HPtuner already, and the bling factor.
Cons: Could be costly, but could be on par with option 1. I think the 4L60E would be nice to be able to control, but probably would need to be built up at some point.

4)N20 5.3L Probably run it as recieved, decent sized cam and headers and maybe some slightly ported heads. Would also run a 4L60E tranny.
Pros: Its a gen III engine! Would probably be a lot more reliable, I'm pretty familiar with these engines, I have HPtuner already, and the bling factor. I think the 5.3L would be less costly and easier to find than the 6.0L
Cons: Could be costly, but could be on par with option 1. I think the 4L60E would be nice to be able to control, but probably would need to be built up at some point. Running nitrous safely still costs a little money, plus I'm not a big fan of nitrous.

So thoses are what I'm thinking. Money is a concern, but obviously all options are going to cost. Plus, if I got a gen III engine I could sell the TPI 350 and tranny to offset some of it.

What route would you go and why? Also....do you see any other options I'm overlooking.

[70rs/ss]

6.0/4l80e, that's what I am doing anyways!