Transmission/Rearend Overall Ratios
I calculated these trans/rear end ratios researching rear ends for my winter '70/L28 project and thought I'd share it with everybody. I called the 77-78 trans a 280a and the 80-83 a 280b due to their
different ratios. The ratios shown are TOTAL (including rearend) which helps compare each gear overall. Sorry I didn't include the 3.54 and 3.70 with the 280b,but the 280a and 3.90 was what I was focused on. BTW, the speed in gears at redline was what my old '76 with 205/70-14 turned, so don't blast me. "...for illustrative purposes only". Notice how a ZX trans with 3.90 is almost identical to a stock 240(!) Hope the columns line up ok for everyone.
| Gear | 240/3.36 | 280a/3.36 | 280a/3.54 | 280a/3.70 | 280a/3.90 | 280b/3.36 | 280b/3.90 |
|---|
| 1st | 11.92 | 11.15 | 11.75 | 12.28 | 12.95 | 10.28 | 11.94 |
|---|
| 2nd | 7.38 | 6.97 | 7.35 | 7.68 | 8.1 | 6.24 | 7.24
|
|---|
| 3rd | 4.77 | 4.39 | 4.63 | 4.83 | 5.1 | 4.39 | 5.1
|
|---|
| 4th | 3.36 | 3.36 | 3.54 | 3.7 | 3.9 | 3.36 | 3.9
|
|---|
| 5th | | 2.9 | 3.05 | 3.19 | 3.36 | 2.5 | 2.9
|
|---|
| MPH AT REDLINEwith 280a |
|---|
| 1st | | 44.4 | 41 | 39.2 | 37.2 |
|---|
| 2nd | | 68.2 | 63 | 60.2 | 57.2 |
| 3rd | | 111.5 | 103 | 98.5 | 93.5 |
| 4th | | 140.8 | 130 | 124.3 | 118.0 |
| REVS AT 60 | | 2434 | 2656 | 2680 | 2822
|
Bryan, IZCC #728
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