Igor,
Need a bit more info on your SKILLZ. Can you fab stuff, do you have power tools, welders etc.
If you can fab stuff, then all I would buy from the JTR kit are the setback plates and spacers for the motor mounts.
Depending on the smog testing requirements in your area, get a model that is exempt.
Check the floors and frame rails and under the battery tray for rust especially.
LT1 V8s are good performers and can be had for around $1000 to $1500 if you keep looking. Check ebay and the classifieds. T56 or 4sp Auto...depending on your preference, but auto may be cheaper and easier to install. Remember all the little things like:
Driveshaft,
Exhaust
brakes
belts
hoses
nuts, bolts, wiring and so on and so on.
You will have to be VERY frugal and make alot of the stuff yourself and look for very good deals to stay within your budget, but it is possible.
Tim