Streetmaster 318 vs. Performer for street use

doktor_x said

This makes me wonder about speedometer accuracy in general with these cars. Mine is weird in the other direction. Rear is tagged as 3.21, tires are 195 75R 14 and GPS shows 72 MPH on the speedo to be 65 MPH actual speed. My intended fix is to stuff a 235 60R 15 under it (two birds w/ one stone).

The allen screw previously mentioned is inside the vacuum canister. You'll be able to feel it by sticking the correct-sized allen wrench in through the nipple.

Click to expand...

Thanks, I was just thinking the same thing about the speedometer accuracy on these things...

I just went out for another run in the Dart (found some wires for 5 and 7) and used a program I have on my Iphone called Dynolicious, using the gyroscope in the phone it acts as a virtual Dyno and is supposed to be quiter accurate. One thing it does accuratly is 0-60 time.
Mine was 9.2 on average. I'm not very impressed with that at all. I'm thinking with my setup I should be pushing close to 250 horse if not more? The car weighs aprox 3k lbs, surely that should be more like 7 second 0-60?

What is the exact weight of a '73 2 door Dart with a 318 with all the seats etc. still in place?

Also with reference to speedo's, the Dynolicious app had me at 90 kph when my speedo said 105 kph.

What is the correct tire size to use as a reference to calculate speedo accuracy?