As you are finding out, parts for these motors are really expensive. This isn't a small block Chevrolet when it comes to buying parts. In spite of this fact, used things are very IN-expensive (and I still can't figure that out). On this forum, go to SHO parts - Classified and the 1st entry is "lots of lightly used..... by 93SilverbuttetSHO. Scroll down the pictures and you will see a fabulous looking 3.0 for $100.00. I wish mine looked so good. Granted it is in Arizona, but you probably know a guy who knows a guy who has a transport run.... well you get the idea. If you don't want that one, eventually one will show up in your area.
If you still want a "numbers-matching" SHO, get a lot more information on the oddities of this motor. I don't really think it is the torquing sequence and 3 people will give you 3 different answers on that topic (something about starting in the middle and working outwards). I know nothing about these motors (except that parts are whoppingly high priced)
Let me give you a little story on a motor I do know - a Y-block Ford from 1956. Every motor in the universe aligns the cam using a mark on the crank gear with a mark on the cam gear..... except this one. You put the crank gear where the dot is at 9:00, take the chain and count 13 links and rotate the cam (to about 9:00) and install the the cam there. Who could figure that out if you didn't ask. There is only 1 way to do it right and lots of ways to do it wrong.
Get lots of people involved and rule out the gasket placement (on the Y-block, it says "this side up", but it doesn't tell you you have to apply sealant around the water passages.... things like that.
You might had a certain pride in getting something running that no one else could, just make sure it makes sense. And if it runs again, read the codes to figure out what may really be wrong.