You're referring to the Ellis Mountain G35, right?
I had the most awesome flight this past weekend with one of those motors in my 29mm Qubit from Art Applewhite. Prep consisted of removing the ejection charge & a little masking tape for friction fitting the motor.
The EM motors have a low peak thrust but that four second burn.....<sigh>
It climbed to over 500ft during the burn phase, immediately turning over & gliding back to the ground safely.
It was without question the coolest high drag rocket flight I've ever seen (much less actually been responsible for)!!!