I am switching over to a vented optispark system and when I started to reassemble, I noticed you have to change the actual timing set, (actually the camshaft sprocket gear) Has anybody ran into this before and if so did you have to buy a new set or can you just drill the old one out? If so what size hole do you drill?

Need help quick- Thanks for any replies

 

if you change to the vented type you have to change timing cover, cam, vented opti vaccuum harness, a small intake manifold fitting, pcv hoses for a 95-97 f-body ( if you want to or get a small tee) . The cam has a longer dowel pin and a bigger hole in the front. I'm sure there maybe a few other things you need, do a search and find the list of GM part numbers you need

 

Here's a write-up on the swap.

http://para.noid.org/~muttvette/opti.html