I got my 71 T-37 140 speedo to the "K" on the brake light twice. With KYB shocks, a 455 with a comp 280 cam and 2.78 gears will suprise you. We have a 22 mile bridge on I-10 near here. You used to be able to haul-ass on it. But that was back in the day. The car had the origional trans and rear end at the time so the speedo should have been somewhat accurate.