I have been using synthetics in race motorcycles and my autos for years and highly recommend them. Pretty much used all brands: Redlline, Mobil 1, Amsoil, Torco, Spectro. I am using Amsoil now because I am a "Preferred Customer" and buy it at dealer price (anyone can become a Preferred Customer by signing up at their website and paying $20/year). They have several types/grades: XL which has a recommended 7,500 mile or 6 month change interval when used with super premium filters; SAE which has a 25,000 mile or 1 year change interval (same filter thing). Use your own judgement on the change interval but I have run my own cars 12,000 miles on Amsoil before changing it and see no degradation.
Mobil 1 has recently come out with an extended drain oil like Amsoil as well.
In my 390 FE engine, I change oil & filters once per year no matter how many miles I drive and I send off an oil sample to be evaluated when I do it. They always come back saying the oil has plenty of life left in it. So far, no bad stuff in the oil (metal, etc).
Amsoil also sells a pre-charger (Canton also has one) that I highly recommend. This thing shoots a dose of oil directly into your engine to pre-load the galleries and bearings before you start it up. Prevents startup damage in motors that are not started and run frequently. I use the bypass/full flow filter system from Amsoil which consists of a normal full-flow filter (all oil goes through it) and a bypass filter (better filter but only filters all oil over a longer period). Here's their weblink:
https://www.amsoil.com/storefront/bf.aspx
I use Amsoil in my Richmond 5 spd and in my locker rear diff. works great. Richmond recommends synthetic in their transmissions (Redline) and they said Amsoil would be fine as well. Locker rear ends may need an additive if they make noise but Amsoil sells that too.
Back when I raced motorcycles, we developed engines by using beaucoup dyno time and I could see the gain in HP when I switched from Valvoline Racing Oil to Torco. I now run Amsoil 20W50 in my H-D engined Buell and saw an increase in HP and mileage there as well.
That's probably more than .02 worth.
Synthetic Oil
Threaded Mode
