The vent tube is on the drives side and I doubt that is your problem. Are you sure you din't blow the dipstick tube out? If not, there is noting else on the side that would cause this unless you broke the tranny case or the pan.
Chris you should really look into a th400 for the kind of power you are making. You are going to be changing th350's like you change shoes. After breaking a couple of pro built th350's with only ~500HP, I built my own th400 and it is holding up well to a lot more power.