Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
Sorry it took me so long but I dove the tanks today and measured them center to center is 5". You might be able to find some higher volume steel tanks that might work. Let me know if you find anything 40cf+. Cheers -Ryan