You've done no reading. None. Not a spec. This is so basic the fools who wrote up the wikipedia page would be laughing at you.
First off the GTS is 10:1, not 11:1. The only higher compression 6g7 is the MIVEC 6g75 which gets 10.5:1 and that is really pushing it on pump gas. The Ralliart 9g galant also got 10.5:1 in it's non MIVEC 6g75.
And no, there are MANY DIFFERENT 6g7x engine blocks. I will list every single one of them (USDM ones that is).
3.0 Liter 12v SOHC: 100% unique, same bore dimensions as the 24v but different journals, crank, harmonic balancer and everything else. Came in many of the shittiest Chrysler products and some low end Mitsubishis.
3.0 Liter 24V SOHC: Comes with 2 bolt mains, forged crankshaft, split forged rods and cast pistons. All versions of this motor got 9:1 compression and a standard intake manifold albeit the Eclipse GTS which got 10:1 pistons and a dual stage intake manifold. If you don't know what this came in you probably can't read at all. Two other versions of this motor came in the Montero Sports but they aren't relevant because you couldn't hope to use anything but the engine block from that vehicle so I won't devulge into the differences other then to say its EVERYTHING else.
2.5 Liter 24v SOHC: This is the 6g73, also came in many garbage Chryslers. It has the same engine block as the 6g72 24v SOHC above EXCEPT it has a MUCH tighter bore. It has the same crank and rods and also 2 bolt mains as the above motor. Heads are the same and so is the lower intake but the intake manifolds that came on the 73 are some of the shittiest intake manifold designs ever put into production.
FIRST GENERATION 3.0 liter 24v DOHC: Came in the first generation 3s platforms. Same block dimensions as the 24v SOHC 3 liter; 2 bolt mains and the same rods but it came with a CAST CRANKSHAFT. Suffered many valve guide and seal problems in the early Diamantes as well. This engine is viewed with the same level of inferiority as the 12v.
SECOND GENERATION 3.0 liter 24v DOHC: Came in the second and third generation 3s platforms. Identical to the motor above except it comes with much stronger cast pistons, a forged crankshaft (ours is the same as this one), FOUR BOLT mains, much higher quality valve hardware and the 3 mm revised lifters.
3.5 liter 24v SOHC: The 6g74, came in the Diamante. The heads are identical to the 6g72 and 6g73 24v SOHC motors. The lower intake manifold fits the wider split so it doesn't work on the small blocks. THIS ENGINE BLOCK IS PHYSICALLY BIGGER IN EVERY SINGLE WAY minus the deck that the heads bolt to which is the same. It has bigger journals, taller deck, 4 bolt mains, forged rods, a crazy strong forged crank shaft.
3.5 liter 24v DOHC: Came in some specific Montero's. The 3000gt guys love using this motor to swap into their cars so long as it comes from the FWD Montero varient. This is the SOHC 6g74 with DOHC heads on it, basically the same engine though since the heads are different the pistons are different as well because the DOHC heads have large combustion chambers.
3.8 liter 6g75 NON MIVEC: Came in the 9 Generation galant and the Mitsubishi Endeavor crossover SUV. Both varients get 10:1 compression in base form while the ralliart galant got 10.5:1. Engines come with 305cc injectors and a NON RETURN fuel setup which is why people use the 6g74 lower with rails when they do this swap. These motors come with a different crank reluctor wheel and coil driven ignition. This engine holds more naturally aspirated potential then any 6g7 to date minus the MIVEC 75. The 75 block is identical to the 6g74 bock except it is bored to 95mm.
3.8 liter 6g75 MIVEC: came in the 4th generation Mitsubishi Eclipse GT. The engine block and rotating assembly is the only thing this shares with the non MIVEC version. It is otherwise completely revamped. Different heads (for MIVEC obviously), different lower intake, different upper manifold and throttle body as well.
Every single 6g7 ever created came with a cast iron cylinder block. I should also mention that the harmonic balancer is the same on every one of the 6g7's except for the 12v. That said the 72's balancer is lightest but if you know what the balancer does then the heavier balancer on the bigger motors should sit sufficiently in your eyes. Our 72 comes with 210cc injectors, the 74 with 270's and the non mivec 75 with 305's. All the motors use the same style injectors so they're swappable given the ability to tune.
I could write an encyclopedia on the differences but that should get you started.
Beyond this, I know how to make every single one of them fast and what you are not even close to considering how to going about this the right way. The 72 block can be clearanced to make room for the 74 crank but the 75 crank is even bigger and clearancing the block that much is going to kill the structural integrity. Beyond that, it has so much stroke that under such a short deck you won't be able to spin it at all because the rods will be insanely short and the pistons massive while also attaining a retarded amount of skirt wear with how far you'll be pulling them below the bores.
You have not the slightest clue how an engine works, much less how to modify it to the ends of more power. If you're dead set on spending the money then drop me a 4000$ check and I will get as far as you can with all this stuff and document every piece of it it that's what it takes to illistrate my point. Everyone here makes such a fuss about how hard it is to make power on these things when it is really quite hilariously easy. You don't need to swap cranks and custom build stuff. Contrary to popular belief there is an easy AND reliable way to make your power (YES, ON THIS SPECIFIC PLATFORM), any amount you could fathom, and for a fraction of the cost everyone throws around when noobs come on here asking retarded questions. A few more odds and ends and for the power you do end up making you'll do circles around people on the course and run times people with hundreds more horsepower drool over at the strip.
Knowledge is the ultimate money and time saver and a one way ticket to glory if you've got the balls to go though with it. I invite anyone to ask me how.
