I've used Brood, Putnam, Fantom, Trinity, Reedy and Orion motors but by far the fastest motors I have ever used and the only stock motors that are in my box at the moment (and I have 9 of them!) are EA Motorsports. I'm not sponsored by EA but I have spoken to him many times on here and by email and think he (Eric Anderson) provides the best service in getting his products to work best for longest. Can Recommend the CO27 and apparently the X Stock is wicked for oval and large tracks.
Just my opinion you understand!
EA Motorsports www.teameamotorsports.com