What's the best head/block combination? I heard it's a 2G head and a 6 bolt block. Is that true?

Ok. Thanks.

Do the 1G and 2G head share the same valve train components? Meaning if I had a build 2G head with aftermarket valves, cams, springs, retainers, guides, etc. Could I swap them over to a 1G head?

Yes. I assume. Honestly, the head doesn't matter as much as you think. Start where it does, Intake, exhaust, IC piping, Turbo, Fuel system, Tuning. This isn't a Honda B18 with LS Vtec head swap. There isn't a magical Head/block combination. Im just tired of people asking how to build a car up to this "spec". Like it's a cake recipe, 2eggs, 3 cups of water, 3 cups of flower, baked in oven for 350 degrees for 30 min. NO, it doesn't work that way. Its not 6bolt + GT3076 + 1000cc injectors + 255 walbro + Link + These cams + these valves + these pistons + that rod. All all set at 20* timing and 11:1 AFR. = 400hp and low 12's. There are alot af variables, and NO TWO CARS ARE THE SAME. Just seriously, build for reliability, tune for power. Either head / valve train will be sufficient, so long as you goals are not 400+ hp. And if it is your goal, you wont make it if you have to ask this question. Sorry to say but I'm not fluffing anything. At this point you should worry more about "will this engine even run reliably for a long period of time under extreme conditions? Trust, I have two backyard motor builds, one over the course of 4 months, and it died to a stupid mistake, and this current one has been going strong for almost a year now, driving to arizona and back, will be going to vegas, and I beat the living shit out of it. But I am almost certain that the car will still be running tommorrow. Thats hard for any person with a DSM to say.