Sounds like you need to figure out what you have first. You need to find out what has been done with your L28 and head. Don't waste money on boring the l28 out if it has already been rebuilt. Have the head CC'd to find out what your CR is.
Best bang for the buck would be to send the Head off to be massaged with a strong cam and mild relief work-the power is in the head. Compliment that with headers, exhaust, carbs, etc...
SU carbs are also great, especially if they have been worked, and very easy to tune.
Triples might be frustrating if you are going to rebuild a set yourself and try and go fast. They do require some carb knowledge to make them work right.
Gearing will also make things fun.
Tune, tune,tune, it takes the whole package to make it fun.
http://youtu.be/NGh6urUlzcQ