Having just done this pursuing more power, you may want to take a look at my
http://www.914world.com/bbs2/index.php?s=&...t&p=2566952 as it presents a few of the options I found during my search. To be clear, I have no affiliation with any of these and cant recommend one over the other.
With that said, I do happen t to have running 2056 with big valve heads that I replaced with the end product of the search. But while it runs well I think it needs some work likely replacement of the stock cam to make it a good running engine.
Any change you consider should include going to the 2056 or 1911 at the minimum and must include replacement of the stock cam if you plan to use carbs or aftermarket FI.
Do all of your research and set yourself a budget and let people know what it is. Feel free to PM me if you have questions.