Those look to be stock low compression pistons. 1.810 compression height is the common one for 318's. Odds are your pistons are about .100" low in the hole. If you are at sea level 8.5 SCR pistons with your cam choice nets you a low 7.0 to 1 DCR at sea level. This will effect how hard the car launches. A higher then stock converter around 2800rpm might be a good choice to mask the low rpm power.