so my optispark gave out a couple weeks ago on my 93 z28. I ordered the msd one off jegs for 93-94. this is my first time changing one by myself, years back when I was just getting into cars I helped change one with my dad on his 95 impala. anyway I took my old one off to find that the spline part is on the engine. but when I look there is a spline on the optispark. how is this possible and what do I do:craz28:? I also noticed taking off the opti that it had a vented cap. not sure if its just a cap or the whole system was converted but figure id throw that info in there.