Your'll gain weight for sure. If you use up less calories than you eat then you put on weight. But weight doesnt equal muscle and where you put it on, could be just be on your belly. then your'll still be skinny and have a gut on you. As for putting on sustained weight , training 4/5 times a week and eating all those calories i recon between 2 and 3 months before you start seeing results. Depending on if you've trained before or not.