Hi Brian,
You will find your answer over on the excellent electric section on this SH forum. Click on the "Set up" section at the top of the 1st page. Just find a plane of the same size and weight of your PT-19, (Flying clown, Flight Streak, Magician, etc.) and use their setup.
You can also use the the standard rule of thumb: 150 to 200 Watts per pound of A/C T.O. weight. (Watts = Battery Volts x motor amp draw) Watts are usually shown in the motor spec. section of a motor website.
Here is the link to the E-flte 15 size E motor that would make a good conversion for your size model.
http://www.horizonhobby.com/products/power-15-brushless-outrunner-motor-950kv-EFLM4015AIf you are a member of PAMPA, you can look at current and past issues and read the electric column. There are good writers there now that have a lot of useful info. In past issues we had many samples of setups and complete systems for all sizes of CL models.
BTW: I have 5 CL models, (all ARC/ARFs) and they are all E powered. :-)