For some reason, not too many stores here stock 10w40 in a synthetic. I'm going to try a few more places, but if I can't find it in my city, what oil is the next best? I'm running pretty much a drag kit at about 11 psi or so and am at about 330 whp on a mustang dyno. Should I go with a 5w40 or a 15w50 in sythetic? Any help would be great.

 

should be able to find 10w30

 

I run 15w60 miller in my turbo cars. Have done for years with good results.

 

do you have an autozone next to you? I grab castrol synthetic 10w40 from there all the time.