Wouldn't worry that with about mpg if you are going to the expense and trouble of putting a 401 in your Gremlin. I am lucky to get 20 out of my six. The difference between 15 and 20mpg probably won't run you another 25 or 30 dollars a month. As for as doing the swap and a lot of people on here disagree with me it depends on what you want to do with the car. If you are going to the drag strip or want something you can pop the hood at the local car show to show off the engine then go ahead and do it. If you are planning on driving it or going to take it local cars for something to do then I wouldn't do it. Two reasons. One I think rasing the hood on a Gremlin kind of ruins the effect of the shape of the little car. People at these shows just want to see a Gremlin. Most of them have never seen one or it has been years since they have seen one. Second that 232 is not a sick engine. You shouldn't have any problems getting in out of traffic with it. If it had a 258 I tell you not to do it. The main thing is to keep it on the road. Just my opinion. [Non-text portions of this message have been removed]