Hi I done a full well almost full conversation on my jato and didn't think about the break. Can someone tell me of a kit or way to use engine breaking and reverse with stock transmission. Please help

electric motors are self braking. The esc you use should automatically brake for you., some even have drag brake, some you can adjust the percentage of brake.

I was told I had to drill holes and put pins in the tranny plate. Becuse with stock tranny the jato just rolls forward without residence. Do u know of a kit?

This is correct - because there is a one-way clutch bearing in the transmission. Spinning the engine (or now "motor") backwards and the car doesn't move. You will need to lock the Trans into second gear to use the motor as the brake. Otherwise just keep a servo mounted for what would have been throttle/brake and just change the linkage a bit so it is brakes only. I would think you should be able to use a Y-harness to allow the ESC and servo to occupy the throttle channel on the receiver.

Yea I drilled and put a pin in and took out the first gear.