Instead of offering my opinion, which generally tends to wind people up, let me just ask a couple of questions and point out a couple of deficiencies.
You have an unknown quantity on your hands, with respect to the tuning problem. You, quite rightly identify excessive fuel pressure as one (but only one, mind) possible cause of the problem. Have you actually checked fuel pressure? Have you put a timing light on it, to see where the timing is? Have you looked down the throats of the carbs, to see what is happening at idle and when you crack the throttle? If not, why not? We're not there, so there is no way we can fill in all the blanks. That is your responsibility.
Then you say you have an oil leak at the rear of the engine. Yes, that could be a rear main seal leaking. Or a rear intake seal leaking. Or a rear cam plug leaking. Have you actually removed the dust cover, to see if you might be able to determine exactly what is actually leaking? If not, why not? The only way you are ever going to learn what is actually leaking is to actually start looking for the leak. Again, we're not there, so we have no way of looking for you. The job of identifying the source of the leak is your responsibility.
What leaves me scratching my head is you may have a couple of very simple issues that you need to address, but you are already in high gear, wanting opinions on whether or not you should rebuild/replace the engine. Have you considered lifting up the radiator cap and just driving a new car underneath it?
What I am reading in your posts is that you really haven't done much of anything, to ascertain what is causing these problems. What you need to read in this post is that it is impossible for us to diagnose your problems without complete details. Do all of us a favor, by reading
this post, before asking for any further help. In order for us to assist you in dialing in your car, you are going to have to recognize, realize and accept you are the only one who can lay either eyes or hands on the car, so in asking for help as you have, you are asking the impossible.
I know this sounds harsh, but how can you expect us to help you, until you are willing to start helping yourself? Do your homework and you will likely discover the source of these issues. If you still can't sort it, you will at least have enough details to provide us, so that we can give you some assistance. Until then, we all have the same problem with spinning our wheels.
