Been playing around with the 757-200 today and decided to fix the contrails being out of position.

Backup your aircraft.cfg first.

Browse the aircraft config until you find [GeneralEngineData]

you can either remove these lines or comment them out ( comment them out is safer ) with // before the line so they look like this

//Engine.0 = 2.60, -17.0, -3.8                    //(feet) longitudinal, lateral, vertical distance from reference datum
//Engine.1 = 2.60,  17.0, -3.8                    //(feet) longitudinal, lateral, vertical distance from reference datum

Now copy and place this in below

Engine.0 = 2.60, -19.0, -3.8                    //(feet) longitudinal, lateral, vertical distance from //reference datum
Engine.1 = 2.60,  23.0, -3.8                    //(feet) longitudinal, lateral, vertical distance from //reference datum

This should give you almost perfect contrails coming from the engines ( yes both of them ), feel free to adjust lateral numbers but remember the higher the number the further away from the engines they will be.

These numbers i have supplied are different due to the way the aircraft was made ( I think ) but normally they would be the same like in the preview of the comment out part.

Here is an example of how mine look now, not perfect but 100 times better. Also i can not share the contrail effect as i don't have permission.

Click the image to make it bigger

Awesome. Thanks!