From what I understand, that is a gen2 because it was not built at the Romeo MI plant. It was built in Dearborn MI.
A replacement engine of any sort is better than an old one. I also would not fear a new or rebuilt gen1. Most were great. Many of the failures were owner created due to not understanding the nature of the engine.
How many miles are on the car, and the new engine?

 

Agree. I have a 2018 and I had a Gen 2. Odd issue with the block being mismanufactured so I got a new replacement in 2023 and it was another Gen 2. At that time, there were 13 on the shelf and I was able to get one inside of a week. I wouldn't be concerned with the engine being replaced. Mine runs great, if not better, compared to the first Gen 2 I had.

 

Also, how many owners has it had?

 

I’ll post the link to it below, looks like it is at 24k miles. With 4k on the new engine.

https://www.parksfordhendersonville.com/inventory/used-2018-ford-mustang-shelby-gt350-rwd-2-door-coupe-1fa6p8jz4j5502084/

 

Thanks for sending the listing.
As much as you like that car, and it’s probably talking to you in your sleep, I think you can do a lot better. Took me nearly 2 years to find mine. Shoot for a 1 owner, 10k-15k mile car. You can get one for under $60k. Just my opinion.

 

I’ve had two get sold from underneath me, my fault for not depositing. But a 19 and a 20 both sold while I was going through the process and toward the end. Thank for all the input, I really appreciate it.

 

If you like the car, I would say go for it! It is a brand new Gen II engine with 4,000 miles on it. It looks pretty clean and the only things I see are a catch can and a shift knop that are not stock. I personally am a fan of the Ruby Red, I just don't see that many, I almost bought one but someone just beat me to it only to bring it back because of rust on the brakes then the offered to me after everything was replaced but I already had my Lightning Blue. Why get a 15K mile car vs. this, how is that better. I wonder if the dealer can tell you something about the previous owner or got it at auction? Don't pay full asking price see what they will do.