I raced my Tii with the stock injection, I did increase compression ratio and add a better cam but the restriction comes with air and fuel intake with the stock injection system. With the setup I had with my engine, I had to configure a special switch on the throttle linkage to trigger the cold start injector at full throttle so I wasn’t leaning out the engine, and even then I was at the limit with the fuel air ratio. The intake of the injection system limits you on performance. You need to convert to a multiple throttle body injection system and finding this system is very hard and expensive. Better to just add big side draft carbs.