Engine is a 355 with 177 weiand blower. Street strip car running 7.6 / 1/8 th mile. Trying to get a little more out of it so got a spring kit for the distributor. The springs that are in it are the heavy silver ones. Timing right now is set at 17 initial and 32 total , all in by 3000 rmp. I want to bring in timing sooner to see if I pick up any thing. I put the two light silver springs in and now timing is at 17 initial but jumps to 38 total without changing anything else. Looking at the msd instructions do I need to change the bushing too in order to limit total timing ? If so which bushing do I start with?