Re: 1987 carpenter F156s 5.57 ratio swap to 4.33
I hope your bus has a manual tranny, because 4.33's are going to suck ass with a 7.3L AND an Automatic... you will lose a hell of alot of power on the highway. But, if you do have a manual trans, with some deep starting gears, it won't suck AS bad... And, I'd turn up the fuel a bit to that 7.3L too, so you can crank a few extra horses out when you're flooring it to climb a steep hill. lol You never want to gear a 7.3L, even if it has a manual trans with anything higher than 4.78's and that's pushing it the limit there. I know because my bus has a 6.9L IDI and an Allison AT-545 auto trans, with 5.38 gears. I can do 45mph @ 2500RPM's, Yes, and that sucks as well. But, remember there's a reason they gear buses low, because some engines just don't have the horses to turn anything higher.... I seriously would try to find a 4.78 if I were you.
Don't think I'm hating on you or anything, I'm just telling you from experience. I'd hate to see you spend all that money to swap it and then you wish'd you hadn't. lol =D
"IF it ain't broke... Don't screw with it and end up breaking it!"