Welcome to the inliners board
Always good to get new members.
I'm not sure what you're capabilities or past experience is like but if you're new to hot rodding or to projects of this size you may want to slow down just a bit. Doing all of that stuff at once is too much for most people. You set a first goal and do that. Then the next. The idea is that at the end of each part you've got the car/engine running and capable again. You see it works, you move on to the next stage.
For example your goal could be to swap over the the Cliffords head.
My first and foremost goal, which is not complete yet, is to convert my 250 L6 over to full multiport injection controlled by an aftermarket computer. I'm accomplishing this by building an intake manifold from scratch with machining and welding. I took a spair cylinder head off an L6, a spare intake, exhaust and carb and two complete EFI setups off of injected GM cars and began modelling. (Quick note: I'm in 2nd year mechanical engineering so I'm pretty good with precise 3D computer models and what not.) So right now I have a complete intake modelled on my computer complete with twin throttle bodies and I have 2D plans drawn up for the machine shop, and that's as far as I am. I can send you what material I've managed to put together so far and/or post some pics if you think it would be useful.
I also built and tested (mostly) a Megasquirt V.2 EFI controller. It's good to run the set of 6 injectors (2 per port) that I plan on running. It's fully programmable, customizable, you can change fuel maps on the run, datalog. It's a DIY system so there's a lot of work involved, but not a lot of money. I've had the system working on the bench including all sensors reading and constants configured but I haven't actually installed it on the car. That is as far as I am on that side.
www.megasquirt.info I haven't done much as far as turbos yet. I've read 3 books on turbo charging and I've done a bunch of calculations to figure how much boost, CFM and whatnot I need but I'm not at the point yet where I can pick a turbo; i have too many over things to figure out yet. That said I am building my setup with an eye towards eventual turboing, fuel pump capacity, injectors, etc. If you check a few turbo books (Hugh MacInnes, Corky Bell) you can figure out how to size turbos fairly fast. Look around online too, there's some real great programs out there. I'll try to find the one turbo sizing program I had.
For pistons I'm not sure. If I recall correct you can get forged 283 pistons that fit correctly into the 292 but there are people on here more knowledgeable than I in that matter. If you're aiming for 5500 redline you're in a good place, I believe (again not the authority) the 292 is fairly easily and safely upgraded to those levels with a few valvetrain parts and a good dampener (dampener - very important).
I can't speak for the Weber-Redline EFI kit, or for the street head from cliffords. I would really like to get the clifford head as most of what it involves is what most of the fast people on here have done (lump port conversion). But I can't actually speak from experience.
Good luck with your project. Keep people posted online here, I can't speak for everybody but I love to know what worked and what didn't and how everything is going. Welcome to the board!
