I am getting a cr 10 5s in the next few weeks and have a large job for it. It’s a custom dash for a car, about 18 by 8 inches. I’m looking for a strong material that will hold up well. Also something that will hold up to high summer temps, say 90 degree outside temps so probably 150 inside. Not sure possibly high temp pla or a pla carbon fiber mix. I know there are a lot more out there but not to sure where to start. Thanks

You did not mention how hight the print will be. It it’s not too high, this might work with either ASA or ABS, although I prefer using ApolloX or TitanX instead as both tend to warp a whole lot less than the standard version of these materials. But the CR10 being an open framed printer, you can still expect to see warping if the print has some substantial height like 5" or more.
High-Temp PLA works nice, although in my experience it oftens takes a little bit of tweaking to print like normal PLA. Please do remind that this kind of PLA needs to be annealed after printing before the high-temp resistance kick into effect and also that annealing parts might lead to warping or deformation as well.
If this is your first large order part, you might consider it a test-case as inform your customer that it is. They might be both willing to let you take your time or try different materials if a first choice fails.