The previous owner of my 73 240 installed a differential from a 510, but doesn't remember what ratio it was. Can you determine the ratio from the folowing numbers? The numbers on the bottom of the casing are: 213

72 5

T 41

At least he saved the original differential. What would be the ratio on the original(I don't know if it was stock either, because there was another previous owner). The casing numbers are as follows: Top- 209

T24

Bottom- 38311

E4600

209

Any suggestions are appreciated. Thanks, Vic.

tanny@frontier.net

ps. The 240 tranny is 4 speed manual. Don't know what tranny the 510 had.

If the 510 diff is from a manual transmission model it it more than likely a 3:90. This is the most common ratio for 510 R-160 diffs. Not sure if there were any other ratios available in the 510's besides the 3:90's.

If the original diff for your car is for a manual transmission, it will be a 3:36 and if it possibly came from an automatic it will be a 3:54. Since I am not sure where you are located I am giving you the US spec ratios for the R-180 diffs. Other ratios were available in the Z's that were delivered elsewhere in the world.