I've got a long block from a 97 cobra. I purchased it in 2018 with the intentions of building a boost motor but have too many issues with the car itself to do any motor work.
I purchased it from Bill Fox's Mustang in PA. They claim it has 50k miles on it. I've never started it up or done anything other than received the shipment and moved it around in my garage. I'm located in Western NY, if you want to cover the shipping we can work out a deal.
Contact @racebronco2 he usually has some in stock. Just got one from him a couple weeks ago, ships from Cali but reasonable price. Gotten multiple from him over the years.