Cyclone gear box - need help

[1965LONEWOLF]

My buddy just bought a cyclone gearbox for a 4x4 pulling truck , I have a profab and its comes with a gear chart and tells you with what rearend gears you have with a turbo 400 tranny it tells you your final gear ratio - I run 6:20 gears front & back with a turbo 400 and a 205 transfer case and I have a choice of a 18 gear whish is a fast gear down to a 24 gear which is a slower gear - Problem is he bought this setup and it comes with not gear chart or anything to compare gears and ratios ? all the profab guys know when you say your running a 18 gear m that's a high gear and you better have enough motor to keep it turning ? so I am looking for help for my buddy , any help you have let me know ? thanks

 

[DISTURBED]

The only help you need is to sell it and buy a profab or scs. Why would anyone by one of those for a pulling truck. They are for mud trucks with a fraction of the hp/tq.