A pre-smog MGB makes 98HP, all day long. 120HP is not a stretch. Mine makes 140HP. No cutting, welding, fabbing or such. I get between 150K and 200K miles on an engine. I've built bunches for my customers. No comebacks.
If you want a hot MGB, go the BOP/Rover V8 route. $3K will get you a reliable 250HP, engine weight is the same and it's pretty much a bolt in. I'm building one now. Or the Mazda rotary route. I've seen the big iron V8 conversions, mucho modding, and they don't go around corners well, but they do give a thrill when accelerating. If that's your bag, go for it.
Another cool engine would be the Ford 2L OHC BDA engines. Not much modding to fit but they do cost a few $$$$.
The 2TC has 70HP stock. You will $pend a few clam$ to get big HP, plus all the fiddling and futzing to make it work. Nitrous is great for hole shots, but IMHO not worth the expense.
I have pared all the weight from my '68 OTS that I can and still have a pleasant long distance tourer, wife must be comfortable, and the wet weight is 2378 lbs, no top. 2000 lbs? Very expen$ive.
Basically, run watcha brung.
