^^Yeah, buy the kit^^ You don't 100 percent have to have it, but an oil injection block-off kit is money well-spent. It looks the best, comes with instructions, and can be installed in about an hour.
Once you have the oil injection removed, get yourself a Ratio-Rite. Look here: Ratio Rite This handy device makes mixing your oil SO much easier, and eliminates the guesswork.