Also, if the LT1 is the same as the ones in the Vettes (pretty sure it is) check the waterpump for water out of the weep hole. When it goes and not caught in time, it will take out the optispark unit (was $1200 when I had to do mine). Waterpumps on the vettes lasted about 60k miles. I would have expected this one to be replaced already.
Besides that, the LT1 was a very reliable engine. Had very little problems with mine. All the other stuff like ABS, the chip in the key, trunk release, window motors were problems, but cheap fixes.