Is 2:45 realisitc?

You have a good foundation based on what you shared. Probably 2:45-2:48. But I don’t think that you have enough pace specific training for the distance though.
I would recommend MP runs ranging from 12-16. These are hard but will get you fit for the distance. It may be too late to safely implement these as you don’t want to force the issue and overtrain. But 12-16 miles incorporated within your long runs will give you that strength you need over the last 10k. I would try to hit 6:12-6:17 on these runs. So actually a tad bit faster than goal pace. Alternating them every other weekend is a good approach with the other long runs being easy or moderate. Maybe you and your coach can discuss incorporating some longer MP miles in some fashion before CIM. Good luck!

Not for your first one, and not off that amount of mileage.

It's feasible for someone running 100-130 miles a week to be in the ball park of doubling their half marathon and adding 5-8 mins; but for someone doing 65 mpw, it's more common to add 10-12 mins.

Also, very few people nail their first marathon. They always underestimate it in some way.

In order to break 2:45, you'd need a big jump in fitness throughout this block.

Chipping in here because I had a very similar situation (pre-super shoes, 2019). I ran 1:18 for the half in March, then my first marathon in 2:51 in November. Ran 65-70 miles, did no long tempos either because I did not want to change too many things at once coming from 10k/hm training. My best long run was similar pace to yours as well. I'm not super fast, I ran 17:15 for 5k on the roads that summer and ran similar 800m reps as you, maybe that helps with the comparison.

I was 30 and I am female, and pretty short (5'6"). So if you are younger and male, you should have better muscular resistance and probably a longer stride. I suspect super shoes would help with the fatigue at the end as well. So yeah, I would say safely under 2:50, but 2:45 maybe a stretch.

Perhaps sub-2:45 is possible if you are more suited for the marathon distance than the shorter distances, but I think you're more likely to crash and burn than achieve a sub-2:45. Yes, 1:18 half is equivalent to 2:44 on the VDOT calculation but I always found those calculators to overestimate potential marathon time. I think you need a longer bout of marathon pace in training to really know what kind of shape you are in. 10 miles at marathon pace isn't going to be that difficult nor should running over 7 min pace for your 20+ mile long runs. A better indicator would be 14-15 miles total at marathon pace as part of a long run in which you are working but not totally maxing out at that pace.

It's always better to go out a bit more conservatively in your first marathon than to do a stretch goal. There's something always unknown and unexpected about the last 10k if you haven't done the distance before. Sub-2:50 would be a safer goal but perhaps on an ideal day with great weather, a flawless buildup, and solid nutrition before and during the race you will get sub-2:45.

2:17 pace group for real? Did they then have a 2:20, 2:25, 2:30, etc.?

You said you wanted to lose weight, if you do so be sure to be careful since underfueling can really mess things up. Awesome training and good luck!

In the 70’s, wearing rather primitive shoes by todays standards, averaging 5 miles per day, with very little variation, I ran 2:55 in my only marathon.

So, unless you have little talent, given that your training is so much better than mine

was, I bet that you’ll run much faster than 2:45.

I have concerns.

1. I don't know how a runner realistically targeting 2:45 is doing 8x800 in slower than 2:45. It doesn't mean you can't race 2:45 for the marathon (and I think you can), but wow you must not have much speed. This will eventually be a limiting factor if you don't address it.

2. A runner months into marathon training, training consistently for over a year as you describe, doesn't usually have 5-6 pounds to simply "drop." Be careful with new food restriction when training seriously.

2:17 was the OTQ standard. So yes im for real. I know the guy that paced it.
where the next set of pacers started - that i do not know but 2:45 seems a reasonable pace group.

Even if they don't have an official pace group, there will be an unofficial group of runners trying to run under 2:45 and forming a small pack. I've been in a couple of these groups at smaller marathons before.

No.

If you're anything like me...

You'll come out too fast and then get cocky when you see 1:16 on the big digital timer at the half mark. Then you'll feel the effects of your inexperienced refueling strategy really hit at 36km and your pace will slow to 4:15. With the finishline insight, you'll suffer seizures and ruin your time with a 14 minute final kilometer.

Disagree. Respect, but do not fear the distance.

I ran 2:38 for my first ever in October off of ~55MPW no LRs over 18 miles. Nail the fueling, do not panic if you get out too hot, and don't assume you'll hit the wall.

If you have a goal, do what it takes to hit it; you may end up blowing it out of the water.

What's your running history, though, compared to the OP?

Something like 60-70 miles/week OP? Going off of the 2.5k miles for the year. That's going to give you a chance. The workouts are good but leave a little to be desired imo. You still have lots of time but I'd like to see some continuous running at GMP & some threshold type workouts. CIM is fast but the front half is decently honest. You do get some rollers. It's when you get to mile 20 there isn't an uphill left & it's just a super gradual descent to the finish. If you're too aggressive you can't take advantage of the closing miles. It also depends on the day. It could be warm. There could be a headwind. Adjust to whatever conditions you get. 1:18-mid is borderline for sub-2:45. You need to have great endurance. How's your speed? If your 5k is relatively faster than 1:18-mid then I'd probably say stick with somewhere in between 2:45 & 2:50. Nothing suggests something way faster than 2:45 so I would pace the front half right at 6:20 or so. Then see if you can run closer to 6:15 past 25/30k. Set yourself up for success.

You'll probably come up short, but the good thing is that the last four or so miles of the course are flat. Regardless of the hype ("CIM is the fastest course in the West"), the CIM is not easy. I've run it six times (Only because it's part of the USATF Pacific Association Grand Prix road series). Your training times aren't bad, but I believe you'll come up short. My advice would be not to focus on speed but rather distance. Do a couple of 28 - 30 milers before December and amp up the weekly mileage to about 100. My race advice: take it very easy until the half, don't try to maintain target pace going up the hills.

For every person that did blow it out of the water, there are 99 that did not.

I did 241 off of 65mpw so you can do 245 - but pace evenly; last few will be tough because of fatigue