you will need guide plates installed into the heads, you can do the drilling but i recommend having a machinist do it since you're never done them before.... also you will need hardened pushrods or else the guide plates will eat right through them..... the 1.6/1.5 setup is good even for a non race motor, the rocker ratio affects cam lift, but it depends on what cam you already are using and what kind of valve clearance you have, if you have a stock to mild cam it can be an easy way to get a little more juice out of the motor, i've never done it myself though so i'd wait on someone with a little more knowledge on it...