brand new silvy LT 4.8 almost time for first oil change. Don't have a clue what to use.

 

chances are its probably conventional but synthetic is always nice if your willing to pay the extra buck

 

When i put my new engine in, its getting the royal purple treatment all the way, im trying everything to get the most mpg's......or maybe thats how i justify it all...

 

I put amsoil in but that was after the truck had about 40,000 miles on it.

 

It really doesn't matter as long as you stick with one or the otherand do regular changes.

 

I beg to differ. Every car I've owned I have run conventional and synthetic and you can always tell an immediate difference in power once you switch to synthetic. I would stick the 5W30 Truck/SUV Mobile 1 in there. Mobile 1 is all I use.

 

hey is it true that once u switch to synthetic, its bad to goback to conventional?

 

Well the thing is they say that synthetic and conventional oil won't mix and it can cause problems. I personally don't think there is a big deal with changeing back but you should make sure you drain the engine real well. Ofcourse either way, when you change oil you never get ALL of the old oil out so your gonna mix a little bit. Haven't had problems to date though so don't worry about it.

 

i have used both and I don't think it matters in the long run.

 

what's the deal with this royal purple stuff? is it just magical or what? its like two dollars more per quart than anything else at o'reilly...