tmanbuckhunter, I wore myself out over the past 2 weeks researching the T6 5w40 Rotella. I ran nothing but the T6 when it was a 15w40 in my water cooled metrics. I found no negatives from anyone on the 5w40 T6 with regard to the TC motors. I just cant feel comfortable using the 5w40 syn in the motor until it has some track record over a few years.

 

doing the break in on the 124 with dino (valvoline 20w50)

after that, S&S was nice enough to send me 4qts of their 20w50 synthetic and a filter when I registered the engine. once thats done, Ive got 2 cases of Lucas 20w50 syn v-twin oil sitting on the shelves. Im looking forward to finally being able to run the synthetic (i did a LOT of oil changes last year, synthetic damned near doubles my intervals)

 

Really old thread but I did find 6 qts. of Quicksilver 20W50 synthetic at Wally World.

In the clearance section at $2.50 a qt.
At that price, I cleared them out.

 

I have run the Quicksilver 20w50 Syn for several years in my TC's. Very happy with it's performance.
It is noticeably quieter (TC clatter warm) then the M1 or Amsoil with hot motor. It was always available at my local Wally SC and priced low in gallons. I hate to see it discontinued if that's the case.
End of last season I started using the Mobil 1, 15w50 auto oil. (crankcase only) This oil was even cheaper than the QSilver and my TC stayed quiet. I will continue to use the 15w50 as long as the price stays as low as it is currently.
I do not run synthetic oil in my primary.

 

Mercury know a little about Evo engines. They were casting crankcases for Harley in the late 90's.

 

Interesting!

Those were supposely the more robust years (post 1995).