My two boys (8 and 5) ride with me in my 89 F-250 Lariat 4X4. My oldest sits in the front seat via booster seat (no airbag) and my 5 year old in a child seat in the back. My 5 year old is about to reach the weight limit max for his child seat but as it is a bench seat, once he is out of his child seat there is a safety issue. The back of the bench seat has a gap between the top of the backrest and the bottom of the window. The back of his head would not have any protection and would be at window level. Other than purchasing a larger child seat intended for kids that have disabilities, do any of you have any advice on bench seat options? Is there a larger bench seat? Any help would be greatly appreciated.