[REDrum]

I drank the synthetic "kool-aide" years ago...

I owned an '86 K5 with a 350ci and always ran on Mobil 1 synthetic in the crank case, changed every 6K. It now has 430K miles and still runs strong. (albeit the 700R transmission is another story...)

Today I run full synthetic Amsoil or Motul in my street and race cars religiously. I swap it out at 6K on the street cars and every other event for race.

I also use Motul engine flush every 3rd change.

If you buy synthetic at the right price and change it yourself at 6K its cheaper than jiffy lube every 3K with dino oil.