Because this information has never really been disclosed let alone asked, there is very little information about this. The 777 series will be another major “family” that has been reworked. Take a look at the CRJs. Technology and other advancements within the app have allowed developers to expand their development to areas that weren’t possible just a few years ago. That said, if you set a power setting on say the CRJ700 and then jump in the 1000, the 1000 should have a higher fuel flow which would indicate a higher thrust rating. They use different versions of the CF34 all on a similar looking airframe. (I haven’t looked to see if that’s the case but something to consider taking a peek at in your free time). Infinite Flight will generally continue a development practice for future aircraft if its been successful and continues to work. For example, working cockpits and wingflex
Not a dev here but I do participate in the closed beta testing program that Infinite Flight has. Infinite Flight does strive for realism. We do have real world pilots within the group. Some that have flown the 777. That said, the data the team uses is derived from real world sources and then tested by the actual pilots we have with our group.
While we’re not permitted to share any sort of information in regards to what you’re specifically asking for, engine specifications, I can tell you that the Infinite Flight team will try to hit all the marks when it comes to data and details such as this. Our devs, staff, alpha, beta and real world pilots within those groups have a very close eye on the attention to detail and will ensure the aircraft is just about a mirror image of the IRL aircraft. Fuel flow, engine thrust, physics, strobe/beacon light timing and patterns, fonts of words on liveries, fan blade count, tire pressure, gear tilt angle, fuel balance between tanks… you name it everything is looked at. As expected, a small bug here and there is expected but after all, we’re all humans and not computers. 😁
Hope that sheds a tiny bit of light on what it is you’re inquiring.