i need some helpwith this. i finally found out that my 93 z28 needs a opti distributor. my questions is should get the OEM opti or should i upgrade to the MSD distributor. as far as the price the oem is What $225.00 and the msd is $515.00. do the msd add any horsepower or just last longer. also is there a way to convert it to the non vented to a vented distributor. i guess what i am asking is what is the difference between the two.

 

The MSD unit allows for a few degrees of timing advance, so technically you could get a bit more HP out of it, although the stock PCM program(in your case the MEMCAL chip) pushes the timing pretty hard based on the knock sensor feedback. Either will work, it's possible the MSD is made out of higher quality components, but I can't speak from personal experience on that. If you want to get the vented opti you would have to replace the front cover on the motor. Unfortunately for you the '93 is kinda the odd-ball of the 4th gens, you'll probably be better off sticking with the OEM opti.