For my A build, the plan was to use a 259 studebaker, Flight O Matic (similar to Ford O Matic) and a 4.09 rear gear just like what came in the car. Rear end is a Dana 44 from a Lark. Just wondering, what if I switch to a 700R4. Should I still run the 4.09 and probably be more eficient or should I switch to a 3.31. Gearing is a little above my meager comprehension.
Go Navy!! Try this ****...hope it helps.... http://nationaldrivetrain.com/Tech_pages/app_chart.html regards, Leo MT-2 USS Oklahoma City CLG-5
Anything from 3.70 to 4.11 works good with a 700r. If your going with a tall rear tire (32") go with the 4.11. Frank
This is the BEST gear / tire / ****** site I've found. You select the trans and it plugs in the OEM gear range. Cool... you don't have to know that going in!!! Have fun, Gary http://www.compushift.com/support/ratio_calculator
Just switch ******s 1st up and try it out. You should have the best of both worlds just with the O/D added. If still not what you wanted then look at rear gears. Another place to start if considering rear gears is just to compare 1st gear ratios T700 versus the original. Plus take the earlier advice and do some checking on the ratio calculator, as it is all about informed choices and what you are hoping to achieve.
There are two different ways of looking at rearend gearing...one is for comfy highway cruising, the other is for off the line performance. Of course they are in direct conflict! If you want the best of both, you need lots of different gear ratios in the transmission. that's why those overdrives like the 700 are so popular...you can run a steep rearend gear ratio for quick take off, and then put it in overdrive for low rpm cruising. THe downside is they cost money...especially if you need to add in the cost of an adapter to put it on a funky Stude motor
The benefit of the overdrive is to have your lower rpm cruising and still have off the line pull when you want. The common misconception is that lower rpms save fuel and gett better mileage. That is somewhat true but also you have to remember that there is a certain rpm all engines perform best at....too high or too low isnt the best of anything. Too low of a cruising rpm lugs the engine and causes many downshift/upshifts. Personally depending on the weight of the vehicle and tire sizes would make my decision on the gears whether 4 speed auto or 3 speed. You installing a 3.31 with the overdrive would sound to me like a mistake. I say leave the ratio alone,and install the overdrive ****** if you have one or can get one and tailor your rear gear after you find out your tire size you plan to run and what results you get from the combo. You might find that you could even go 4.30 or 4.56 and not hurt your highway driving. I do a ton of gear swaps on late model dodge rams. Most of those trucks with stock 20" wheels and 33" tall tires (factory) use a 3.92 factory gear and the 17" rims and 31" tall tires use a 3.55 rear gear. I have installed many 4.56 gears in these late model trucks with everyone including myself getting upwards of 2-3 mpg and better performance in town also. These trucks are heavy and use a 5 speed auto,and when swapping from a 3.92 to a 4.56 with NO other changes nets you a raised 300 rpm change all the way through the range. Once you start going over 70-75 mph though the mpg starts to drop off. Sorry about the long winded post........must be lack of sleep.....LOL
The Jalopy Journal
