Somewhat surprised to see this has never been posted here! I've been eating this at Robert's parents' house for more than 25 years. It was originally in the Sunset Barbeque Cookbook, the ORIGINAL one from the 1960s. I know that, because my parents had the same cookbook. When I make this recipe, I have to track it down in an old homemade cookbook that I created around the time Trevor was born, working part time, often with nothing better to do. So the recipe is moving here for posterity's sake, which makes me happy. I'm writing the recipe here as we make it, with comments re the original recipe following.
MCGOWAN'S FAVORITE BAKED BEANS
2 - 16 oz. cans pork and beans in tomato sauce
1/3 c. brown sugar
1/2 c. ketchup
1 t. dry mustard
Mix all well. Bake uncovered at 325 for 2-1/2 hours. Serves 6-8.
The original Sunset recipe calls for 3/4 c. brown sugar and 6 slices of bacon, chopped. No need to say why we've tweaked it!