Well anyways, to further discuss the question irregardless of the intent of the original poster or his/her current status and whereabouts, i am curious to see the performance gains by balancing and blueprinting the engine and how this compares from a cost effective standpoint vs. adding nitrous.
The engine may need a rebuild anyways and then switch to non-computer ignition and carburetion.
Then again, if the engine has to come out, then yes it probably would be more cost effective to just swap a 4.3 v-6 or even 8 cyl small block............
2) P.S. Here nitrous is completely illegal---can't even transport it unless you have placards. But it's not enforced.