Ah yes my fine young bottle rocket pilot,the stacks you seek,it may be in conflict with either of the sanctioning bodies(NHRA or IHRA)rules,,Remember,with your 2 gas bottles back there stacks present a problem most tech men will bounce you for,,Check the rules over thoroughly and I'll double check with my NHRA regional tech man,,The only way I think you may get away with the stacks and the gas bottles is if the stacks are contained with a steel plate separating them and the gas bottles,,With the propane in the bed especially,a spark would cause a rather large mess,,I'd think it over and decide what your looking to do with the truck before you add the stacks,,Stacks are cool,but,not something I'd want to do with the bottles onboard... ... ... Andy