Seeking assistance with 2-speed rear end

[redfv08]

Hello All,
Thank all of you. I have been reading for years and learned tremendous amounts. Here is the info needed in order to help me. 1973 ford, 361 gas engine, mild rv cam, 4 bbl. carb. Clark trans with 5th gear at 1:1. final drive is a single speed rockwell with ratio at 6.14:1. According to ford and rockwell this is the highest ratio available. Engine speed is 3400-3500 rpm at a true 65 mph. I have recently acquired a bus with an eaton two speed, model 19050t, final drive 6.57:1 (hi gear). My intent is to exchange the rockwell for the eaton then change the ring and pinion for a more favorable highway ratio. The available ratios for the eaton are 4.56:1, 4.88:1, 5.29:1, 5.57:1 and what I have now 6.14:1. What are your experiences and opinions regarding the best r&p in order to make a better road cruiser? I would like to get the rpm to about 2300-2500 at about 65mph. Is this doable?
Thanks to all for your help.

[chev49]

It is do-able, but probably a better idea just to get a two speed third member with the right gear ratio for yours. and don't forget the two speed switch.,

[frank-id]

Wow, seems like a lot of work for little gain. Gather all information about your present rear axle, as all measurements about spring location, width of complete assembly, pinion location and brake size. Go to a salvage yard for big trucks and buses and find the correct unit and with a 410 gear ratio. Installing a good used axle complete is the best choice. The brake system maybe a challenge to change from a air system to hydraulics. I am changing my old Crown bus from a 410 to a 355 removed from a big rig. Rear axle unit was just $650. Frank

[chev49]

Its an old ford conventional. there are tons of the same 2 speeds in the yards, not to mention on farms, etc. and the parts would be very cheap, not like a coach rear end. the last one of those i sold, i got 1100 for a v drive one from a transit

[redfv08]

Thank you for the info on prices and ratio. I forgot to put the tire size, 10.00-20, in the initial post. I have since found out from a truck salvage yard that the rockwell housing (12 bolt) will not accept a pumpkin with the 2-speed. Also the eaton 19050t has disc brakes and a different bolt pattern (8 or 10 bolt) to the housing from the rockwell (6 bolt) for the brake backing plates. I think the swap with the 19050t is not doable so I am now searching for an earlier eaton, 17,500#, which was an option in that year. This may also allow me to use the dayton hubs I have now rather than change to buds. I also have the original hydraulic brakes with vacuum boosters, not air or air/hydraulic.
To another aspect of this swap. I may have a line on a used unit with the ratio I want. I really want to zero in on the "right" ratio. Any and all info in this direction is of great help.
Thank you all.

[chev49]

Just get a rear end out of your year range of truck. Doesnt have to be ford. i don't ask for the part im looking for in a wrecking yard, i just go and look around and find it - or it will cost me more.

[1of7]

I have a 1978 bluebird. . Is a Rockwell R-155-PX-71 with a gear ratio of 5.29. My cruising rpm (were the engine is happy) is 2400 RPMs. I’m only able to get up to 55mph at cruising speed. I’m looking for either a different rear end with airbrakes or to change out My third member for a two speed. I can’t seem to figure out what I actually need to get and where to get it. Any advice would be much appreciated!