My LS1 has just about 100000 miles I want to know what oil everyone thinks would benefit me the most. I don't know what oil was previously in it.

 

Well, supposedly there is no danger from switching from synthetic to conventional at any time. However, there is a myth that switching to synthetic after running conventional for a while can cause leaks at the seals. I do not know how true this is, but I guess its because conventional is thicker than synthetic. Since you dont know what was run previously, run synthetic if you can afford it. Mobil 1 has always been a proven oil to run

 

What about royal purple?

 

I would use Mobil 1 5w30....its about the easiest to get synthetic that has a proven record. Also Castrol, or Valvoline make a good synthetic.

I have switched to synthetic on every vehicle I've ever owned no matter what mileage and there has been no leaking or side effects. I'd do it.

 

Well.. I recently picked up a 88 Vette with a L98.. Well, I switched from dino oil to Penzoil Synthetic and low and behold.. leaks from the rear main now.. switching back to conventional only slowed down the leak...

Don't know if other have had this problem... but I have read a few story on this and other forums..

 

castrol syntec 0w30... do a search for "german castrol" ...far superior to mobil 1

 

Whatever you'd like.

 

I'm running Shell Rotella 5/40 full synthetic for 20 dollars for a gallon at walmart. It is a great oil at a great price. Can't go wrong.