Hello All,
I have just gotten my first car to work on with the old man. It is a 66 Mustang. The engine is the orginal engine, numbers match. My question is, how much work can I do on the engine? For example being that it is the orginal engine how many parts and what parts can I replace with better performance parts on the engine?

It is an inline 6 with 3 on the floor. I assumed that I should not pull the engine because it is the original. I don't want to go crazy power build up. I just want to improve the performance and learn as much as I can about engines from the old man. I suppose I am looking for your opinion on what you would do with it.

Thanks  

I am on the same boat as you.  I bought a 72 Mach 1 so that I could rebuild it with my dad.  I think the first question to ask is, when you are finished with the car do you want it to be all original or doesn't that matter to you?  In my case I want my car to be a original as possible.  Now when it came to my engine I pulled it out of the car so I could do things right.  The engine also needed rebuilt.  If you are looking to keep the car original then I suggest that you beef up your engine internally and keep the outside original looking.  I have a 351 Cleveland so I bored it .030 over because it needed it, I put in a new cam, new valves, roller rockers, etc.  So I didn't do anything major but ill definitely be able to notice a power difference.  The outside of the engine will be totally original looking.  I hope that helps or at least gives you some ideas.  

Drew