Question about Synth Oil Conversion '89 90Q 10v

["gsethi" <gsethi@corp.webtv.net>]

I am considering changing to synthetic oil (mobil 1)
The car has 121k miles on reg oil and is driven mod-hard in Northern Cali
50-100deg

>From what I understand -I should gradually convert to synth so my questions
are

1. how rapid and what ratio of synth to reg I should use during the
conversion be etc.

2. Is it worth synthetic for my model?

3. I am using 20-50 sae should I change oil type?


Thanks,
Gurdev