I found this five speed and its in an school bus with a 330md,

Could I yank this out and cram it behind the bellhousing of my 390 which cuurently got a t-18 four speed in it? The picture in my book of 4+5 speeds look similier minus more gears and some extra meat.

 

Dory, the tranny you found might very well be a Clark 5spd. What year is the bus ? Clarks were used in many trucks, 2 ton or heavier, from the mid 60s to the late 70s. They are excellent truck trannies. You can still get parts if you need from Eaton, they bought out Clark. I think they still make the Clark design new, but they have eaton's name on them now. I have a Clark 280 series, mine has 6.99/4.09/2.24/1.47/1.00 to 1 gearing. I think it would be a wonderfull addition to an older truck. The gear spread in the 4 spds most of our trucks come with isn't the most driver friendly. If you switched to the Clark, you could change the rear axle gears or run taller tires. This should let you get better mileage but still have plenty of pulling power with the 6.99 first. You'll need the bellhousing and clutch and flywheel from the Bus, get the starter too, just in case. It could also be a NP542....there is also the possibility that it is an overdrive model, but I searched for many years and never found any ODs.......after much thought, I figured that the OD models had the same bad gear spread as the 4 spds did, but with an OD....and that the normal 5spd spread with differant axle gears was the way to go. DF

 

I'll have to check the year of the bus tommorow hopefully, I'd like to get my 3.54 rear back in the truck. The five speed will have some extra guts for highway hauling with out the need for the current 4.10s which cause a major racket at over 65mph....RRRRRRRR. 1.42 would probaly be a good ratio for heavy hauling with 3.54's. Thanks for the info so far