Red Tornado

Since the rebuild (which included plamsa-moly rings), I've now hit the 1,000 mile mark with zero engine issues, all looks a-ok

I've used regular dino oil from the start, Castrol GTX 5W-30 and have changed it 3 times (+200, +500, and now at the +1,000 mile mark).........At what mileage should I be able to switch over to full synthetic --- by the the next oil change (3,000 - 5,000 mi. interval), or should I wait longer?

RED LT4

i WAS TOLD AFTER 1000 MILES IT WOULD BE OK

rws.1

You are fine to switch to synthetic now.

R23HTC

I switched at 1000k, but I've heard so many different stories, I'm not sure what to believe.

C66 Racing

There are actually numerous different types of synthetics on the market and they all behave differently. What most people would think of as true synthetics are either Group IV, or PAO based synthetics such as Mobil 1, or AMSOIL SAE Synthetic 5w30 or Group V/VI ester based synthetics.

There is a lower class of synthetics, the Group III synthetics, which may fit your usage better. This class of synthetic is actually a highly refined petroleum based oil. A typical dyno oil is only about 70% pure. A group III "synthetic" is over 90% pure petroleum based oil. So it behaves much like dyno oil, only better. And it is less expensive than a full PAO or ester based synthetic. If you are uncomfortable going to a Group IV or V synthetic, you may feel more comfortable with a Group III.

The AMSOIL XL line is a group III synthetic, but with higher levels of anti-wear and detergent additives than the typical competitor's oil.
AMSOIL XL Synthetic 5w30

vader86

You should be fine to switch now, going by what a few builders have suggested to me before.

pwrful c4

You can switich now with no problems.

Corvette Kid

I switched mine to a syn-blend after a few hundred miles and finally back to full synthetic. I don't remember the exact mileages, it's not really that critical. I'm sure it was by 1000-1500 miles. This is the kind of thing I only do on my or someone else's high performance stuff. By contrast, the HD diesels I build for a living go right out and run 12-15K miles (normal interval) before their first oil change.

Red Tornado

All, thanks for your input. Sounds like about 1,000 mi. is the agree-upon milestone for the changeover.

Since I still used regular dino for my last change at 1,000 mi. over the past weekend, I'll be more than fine by the time the interval comes in 3,000 or so mi., switching over to full synthetic.

Thanks again all, for your confirmation