I notice you're still on the mechanical fuel injection setup - when you say you were doing 120mph and your foot wasn't all the way down...

Just so you know - the wide open throttle enrichment (i.e the extra fuel when you are on boost) only kicks in when you have your foot right down.

Just a warning to avoid any 4th/5th gear sustained hard use unless you have your toe all the way in! Especially top speed runs

Once your engine is run in - make sure it is properly setup too

Nothing worse than having your new found enjoyment cut short because of an avoidable problem!

P.S - Rod is right, power becomes more addictive than crack