Both of the guys who posted above me were reading my mind. There have been engines like yours go to many more miles, but you have already experienced some problems that signal it is not going to happen for yours, most probably.

Another factor is TIME, this truck engine is now 34 years old, and things dry out and age in that time. I have to school my customers at my marina all the time on this fact. They bring in a 5 year old boat and say "but it only has 50 hours on it." and I have to tell them, "yes, but it is 5 years old, that is what counts." I drive an '84 Ford that just turned 60,000 miles, but things are aging on it, and you can't equate it to a two year old car that has 60,000 miles on it.

Buy a Goodwrench replacement engine, forget the cam swap, and maybe rebuild the quadrajet. You will get a Goodwrench for the same or less than you will spend rebuilding your engine, and get a 3 year warranty.

Just my 2 cents worth.

Don


PS: Welcome to the forum.