I'm pretty new to all this, this is my very first project truck and i was wondering what is the gear ratio and what do i need to do when i get a new tranny in there as regards to the gear ratio and getting that set up with the differential and drive shaft? i'm lookin at either a TH350 Or TH400 for my 67 c10, i'm getting a new 350 in there it has a 283 curently.
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I need some help, i'm pretty new to this
- Thread starter byates2
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dvalentine
Charter Member
You didn't mention what trans is coming out that the TH350 will be replacing.
There are many rear end gear ratios that came in these trucks. BUT, the most prevelent were the 3 :70. If that's what you have you should be OK with the TH350. If you have a 4:11 you might want to go a tad higher like the 3:70 or 3:30.
Personally, I wouldn't go any higher than 3:30. You can get better gas milage on the freeways by using a 3:08 or higher, but the low end performance will suffer.
Val
p.s. You can estimate what rear ratio you have by jacking up the rear end on jack stands. Then place a mark on the drive shaft, pencil, tape, whatever.
Then rotate the drive wheel one full recelotion and count the number of times the driveshaft turns. If the drive shaft rotates 4 times ( plus a little) you have a 4:11. 3 and 1/3 = 3:30. 3 and 1/2 or greater ( but less than 4 ) 3:70.
There are many rear end gear ratios that came in these trucks. BUT, the most prevelent were the 3 :70. If that's what you have you should be OK with the TH350. If you have a 4:11 you might want to go a tad higher like the 3:70 or 3:30.
Personally, I wouldn't go any higher than 3:30. You can get better gas milage on the freeways by using a 3:08 or higher, but the low end performance will suffer.
Val
p.s. You can estimate what rear ratio you have by jacking up the rear end on jack stands. Then place a mark on the drive shaft, pencil, tape, whatever.
Then rotate the drive wheel one full recelotion and count the number of times the driveshaft turns. If the drive shaft rotates 4 times ( plus a little) you have a 4:11. 3 and 1/3 = 3:30. 3 and 1/2 or greater ( but less than 4 ) 3:70.