What weight should I use for my Alpha One? I noticed that Royal Purple and several outher brands list several different weights...Also what does everyone like for their oudrives merc or some outher oil?

"Bad-Habit"

synthetic for sure. Merc's super h.p. synthetic is very good. AMSOIL synthetic racing is probably the very best!

Redline synthetic 80w/140 (bravo xr).

Is Mercury High Performance Gear Lube + the top of the line for Merc? Is that a synthetic or is it a mineral based oil? What is the viscosity? I have heard this is a private labeled Amsoil synthetic. Has anyone else heard this? Just curious.

I use RedLine ShockProof Heavy in my Alphas on the Formula- I have Simrek drive showers and drive reservoirs as well. Never had a problem with them (twin SBC's). Although pricey, I think it's the best lube you can put in an Alpha drive- they run very warm!

I have been running Mobil 1 synthetic gear lube for two years and I swear it shift smoother although that may just be my brain justifying the cost.

What Weight????

75/90

I'm also using the Mobil One synthetic 75 - 90 wt. this year after the Mercury high performance oil turned to green sludge last year. I'm hoping this stuff will work better !

Only one problem I see here is that Mobil 1 has a GL - 5 rating and from what I have been told outdrives require a GL - 4 rating. The differance between the two is GL -5 has additives that damage brass and bronze. Good for rear axles but not for transmissions. Coastal is the only one I have found that states it is good for GL - 3, 4 and 5.