Something I noticed in the 85 is that the shift points noted on the speedo are 10 miles per hour higher than on the 81 and 84 SDs. Third is at 80 MPH.

Is this due to a different rear end?

I think this may be why the 85 does not seem to have the same pickup as the other cars (as well as the fact that it has that oxidizer that works as a pressure tank).

anyone know if in fact the rear ends are different or is this transmission differences?

BTW- after adjusting the boost pressure I now get 0-60 in about 13 seconds.

__________________
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique

The '85 has the 2.88:1 diff.

The others have the 3.07:1 diff.

Not a major difference, and, certainly not 10 mph worth. Probably translates to about 3 mph.

that they would place the shift points so much higher on the 85? Really surprised me that they were that different.

__________________
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique

What are the shift points on the '85?

I'll convert them to engine speed and see if they make any sense.

Are the stock tires 195-70-14 on that vehicle?

If memory serves me, second is at about 47 mph and 3rd is around 78 mph. Kind of hard to tell due to the dots being spread across a few mph on the speedo.

__________________
'99 S420 - Mommies
'72 280SE 4.5 - looking to breathe life into it
'84 300SD Grey - Sold
'85 300SD Silver - Sold
'78 Ski Nautique

Those numbers seem right on the money.

Second translates to 4405 rpm with no slip (figure another 200 for the slip)

Third translates to 4437 rpm with no slip.

I ran the calculations with 195-70-14 tires. I'm not sure if they are stock on the '85 SD.