I got my 2.7 replaced last week, and was recomended to change my oil after 1,000 miles....soo my question is...should i switch to Mobil 1 Synthetic now? or should i run dino oil through the motor one more time
There's a lot of myth and mystery about this subject. The best thing to do is to see what the garage says to do, or better yet, if its a Jasper engine, call them up and see what they say. Keep in mind, if there is any warranty with your new engine, you're gonna want to follow their instructions by the book, so if anything happens, it falls in their lap and not yours. And back yourself up, get it in writing, not just a verbal over the phone. Get something showing what they say to do.
I would get a magnetic drain plug. Change the oil at very short intervals at first.
Something like first 100miles, then 1500, then 3000. Note the metal on the magnet.
After it tapers down to almost nothing, it's time for synthetic.
Synthetic will seat the rings just fine. If fact, in a vehicle with a roller valve train, there'd be no problem using synthetic from the get go. The main issue is that you should really change the first oil at after a very short interval, which is just throwing money away if you're running a synthetic. Basically, you're just getting rid of the teeny bits of metal the oil is carrying around after everything is worn in a bit, and before it causes any extra wear.
NEVER use synthetics for engine break in on a old flat tappet pushrod engine. Almost all of the current ones lack the EP additives that keep the cam from wearing (for emissions/sensor reasons). I'd run something like Rotella T, or some other good diesel oil with a lot of EP additives, and add in a bottle of GM's EOS in this case.