overdrive vs updated rear

[oldmopar]

Presently my vehicles are stock original rear and trans but I have been considering either a overdrive or rear upgrade to handle higher speeds more comfortably (one may get a engine drive train transplant but that is a story for another day).

Now having read the recent and previous threads about overdrives it sounds to me that they do have more then their share of problems and it makes sense as they have more moving parts so would it be a logical conclusion that a upgrade to the rear would be less trouble once the swap is made.

Ed

[James_Douglas]

Go get a gear vendors unit. Pricey yes. Problems none.

James

[james curl]

Be careful about rear end ratios, I have installed a 90 Dodge Dakota rear end with 3.55:1 gears and have P205 75 15 tires on the car. I think the most you could pull easly would be a 3.37:1 rear gear with the P 205 75 15 tires. With the 3.55:1 I am turning 3185 RPM at 70 MPH. With the 3.37:1 rear gear you would be turning 3022 RPM at 70. Either of the two will require a little more RPM to get moving from start. The over drive with 3.9:1 rear gears and a 30% overdrive reduction will be turning 2448 RPM at 70 MPH or 3498 without overdrive. With the overdrive engaged in low gear it would be like starting from a stop with a 2.75:1 rear end and no overdrive.

[Young Ed]

Ed as with anything else mechanical they can be broken or worn out. However the 2 that dad is running have never been rebuilt. They are junkyard/parts car fresh. Supposedly the one in my 51 was rebuilt by the guy who gave it to me. I have no proof other then his word and no knowledge of his version of "rebuilt" I certainly wouldn't be afraid to try one.

[blueskies]

Nearly 14,000 miles on my rebuilt '55 OD, not a single issue thus far. Course it might die the next time I drive it...

Pete

[48mirage]

Like you I have some reservations about the added mechanicals and electrics in the OD units. I am focusing on finding a 3.55 rear end and making the tires are the original diamater. I think this will slow down the RPM's and not interfere with my ability to climb hills. I have a fluid drive in the D30, I've already split the exhaust and gone to a holley 2 barrel carb. I have a milled '54 head in the garage and found a '59 with 8 to 1 compression in the pick and pull. I just need more hours in a day to do all the things I want to do.