Replacing the engine does not guarantee that you won't still have an overheating problem.
Just engine and labor when I changed my engine, it took me about 4 hours myself to get everything disconnected from the engine so it was ready to be pulled. Then took my friend and I another 4 hours to pull the engine, finish pulling anything else that needed to come off and get it to the machine shop. Another 4-8 hours to get everything back in and installed and running again. The rebuilt engine was $400, my cost and my 4 hours plus 8 hours of my and my friend's time and then another 4-8 hours, that's 16 hours on the low side and that's with basic hand tools, no pneumatic anything. I'd say an average mechanic could do it in about 12 hours with good tools and all the right equipment. That'd be $50 on the low side. That's anohter $600. AFAIK, the 1995's still had LT1's so that's gonna cost you more than my 305 TPI. I'd say you're looking at close to $1500 when it's all said and done if you're lucky.
I'd take your car to someone else and see if they can find the problem. Not another dealer.