I have drag raced for many years (Mopars-440's, stroker 440's and 426 Hemi's). Rule of thumb was to use the lowest viscosity you could get away with. This meant a lot of experimenting (run a season, take it apart, inspect it and see where you are). That, plus you wanted to maintain enough oil pressure both for idle (valve train) and full RPM. From that I was able to use 10W30 most of the time (10W40 tops).
Those days are behind me so now I have a 2013 Shelby GT500 convertible. I bought it used from a friend that owns a Ford Dealer (buys one every year). It had one oil change at 1900km. I just did one at 7400km just before storing it. I've always used Amsoil and was disappointed that they did not offer a 5W50 so I used 5W50 Redline and a Ford Racing filter.
I'm reading with intrigue the various takes on what is good and not so good as far as oils, viscosities, etc. especially the Amsoil 10W40/10W30 take. The problem I have with the 10W40 which I assume is the AMO oil, is the excessive zinc and Phosphorus. Would the warranty not be void on the CATS should they fail if you used the AMO oil since it is not an SN rated oil (SL I believe). I'm sure viscosity wise it would be fine.
One of the big deals that was made about the 5.8 trinity engine was the problems the engineers were having with heat expulsion to the extent that they actually removed the grill. If this is a big fear, I'm kind of leary about 10W30 as far as thinning too much from the heat, although it would seem to be the best bet since the MC5W50 shears so much (maybe not to a 10W30 level), but it is an SL rated oil (Amsoil wise)
So is there anything out there that is a true POA oil that has a 10W40 viscosity and is SL rated? That would seem to be the best bet.
Also, for a strictly street driven car that is never tracked would th MC 5W50 not be a good alternative for this application provided it is changed out at 7000 miles?
Just my two cents.
Those days are behind me so now I have a 2013 Shelby GT500 convertible. I bought it used from a friend that owns a Ford Dealer (buys one every year). It had one oil change at 1900km. I just did one at 7400km just before storing it. I've always used Amsoil and was disappointed that they did not offer a 5W50 so I used 5W50 Redline and a Ford Racing filter.
I'm reading with intrigue the various takes on what is good and not so good as far as oils, viscosities, etc. especially the Amsoil 10W40/10W30 take. The problem I have with the 10W40 which I assume is the AMO oil, is the excessive zinc and Phosphorus. Would the warranty not be void on the CATS should they fail if you used the AMO oil since it is not an SN rated oil (SL I believe). I'm sure viscosity wise it would be fine.
One of the big deals that was made about the 5.8 trinity engine was the problems the engineers were having with heat expulsion to the extent that they actually removed the grill. If this is a big fear, I'm kind of leary about 10W30 as far as thinning too much from the heat, although it would seem to be the best bet since the MC5W50 shears so much (maybe not to a 10W30 level), but it is an SL rated oil (Amsoil wise)
So is there anything out there that is a true POA oil that has a 10W40 viscosity and is SL rated? That would seem to be the best bet.
Also, for a strictly street driven car that is never tracked would th MC 5W50 not be a good alternative for this application provided it is changed out at 7000 miles?
Just my two cents.