first of all, you have a V6 3.0L engine. it makes roughly 160 HP and about the same for torque. I don't know if you can fit a small block in that engine bay, but you could do some mods to your six and you will have a good amount of torque.
1. Get a K&N cold air filter kit
2. Get a good set of headers, cats, and muffler
3. Shave the head 1mm to increase compression
4. If you are going to shave the head, see about getting some oversized pistons and bore it out.
These things would give you more torgue and punch off the line.
That would be about the same amount of money or cheaper and still have your original reliability and equipment. I have only seen V-8 kits for the 70-83 Zs.
...on the downlow...
LuZZifer