I'm currently using Kendall 20w 50 and was wondering if i could run the "bottom end" dry with this weight. I have a stroked 351W that is 90 % street driven.
Running it dry is possible.... I quit running 20-50 because it takes so long to get it to the top end at start up. Most engine wear happens at start up when there is no oil protection. If it takes 1 second for a thin oil and 3 seconds for 20-50 well.....you can see where I'm going with this.
If you are using 20-50 for protecting the motor switch to a lighter weight synthetic or a semi-syn.
I would ask the engine builder. That sounds a little thick. There is HP in thinner oil since it is easier to pump. Some new engines run 0w20 to reduce power used to pump it.
When i got my motor built 6 years ago, the guy that built it told me to run 20w-50 all the time. It's not a daily driver, but i dont know why he recommended that weight . I'm thinking of going to a 10w-40 Quaker State or Valvoline(Napa), and a Napa Oil Filter(made by Wix).
I just recently switched from mobile 1 5w30 to kendall 10w30. Besides being dirt cheap(1.60 a quart), kendall seems to have a good reputation and 10w30 is a "safe" oil to run in most engines. 20w50 seems a bit high to me.
20W50 is definitely high. I'm new to Mustangs, but out of all of my other classics, i've never ran anything that thick. Maybe if you lived in Nevada or Arizona. (extremely hot temperatures) I'd go with a 10W40.
I have used 20w-50 Castrol for several years in my Mustang. The PO said the engine was built by a marine speed shop. I recently learned that 20w-50 means the oil's viscosity is 20 weight all the time. The 50 just means it offers the protection of 50 weight when hot. My engine would blow smoke when it got hot and idled too long. I have since switched to straight 50 weight racing oil and although not cheap, it has reduced the smoking problem to almost nothing and my plugs are no longer wet. I haven't noticed any start up problems or any more drag than running 20w-50.
I am about to fire my CHP 347 long block for the first time, so I called them for reccomendation on oil. They told me 20/50, so that is what I am planning on running. I will be sure to prime the oil system just before I fire her up to make sure the top end is fully lubed.
I just switched to Shell Rotella T because since the oil companies have removed the minerals from the oil we have been wiping out flat tappet camshafts. We wiped out a cam in the 68 Stang we built and in a 66 GTO we built. I suggest you read this bulletin if you are running a flat tappet cam.