Well,here goes.Sick of gas motor.Purchase non intercooled 91 3500 with getrag 5 spd.Runs great,leaks at the fuel shutoff solenoid.No biggie.Go to fit this in my old Jeep,kinda looks too big.Went and purchased 97 4bta with a turbo whatever on the back.Runs perfect.This motor needs to push a very heavy,5:88 ratioed 67OO lb 4wd down the road at least 55 mph.So, the 1:1 in the turbo whatever wont work,so go with the Getrag.Will my 6bt flywheel work on the 4 bta?I am more confused now after reading the turbo section.I have a brand new turbo on the non intercooled 6,does it need to go on the 4?The 4 bta is the 120 hp version.Whats it take to get 140-45 hp?Piles of parts.What works best?