Are pretty much right on--my 12 bolt OLDS is listed---(stamped) on passenger side (facing aft) upside down "S7" which is an "ANTI-SPIN 3:23" jacked it up on stands rotated wheel 10 times drive shaft went a little over 32 turns.Went thru local radar speed checks at 2600 RPM and clocked 59/60 MPH 4 times (with 28" tires) so according to Doves book:Smarty: that would be a 355 rear--well we know it aint -- so the CORRECT tach reading should be 2300 RPM/323 gears/60MPH and 28" tires---so the tach is 300 RPM fast:eek2: no surprise there BUT worse the radar check at 60MPH my speedo is reading 46MPH--now thats bad:af: really gotta watch my speed--that engine rpm/tire/60 mph chart is really useful:TU: ---is it reproduced somewhere on this board? Should be a sticky! Best to all Pete:3gears: +1