[Healeys] Help with BT7 (new thread - I got bounced again!!!!!)

[Per Schoerner]

Bob
Yes, you are correct, the speed of the driveshaft is what determines the 
speed. But the different boxes have different speedometer drive gearing. 
So,for a 3000 overdrive the driveshaft turns 3,2 revolutions to turn the 
speedo 1 turn. A 100/6 overdrive does the same in 2,5 turns. A 100/6 
gearbox without overdrive does the same in 2 turns. I have yet to figure 
out what a 3000 non overdrive box does.
Hence the different speedometers.
BTW. sorry about the confusion, I meant tpm of course, not tpi.
Per

Bob Spidell skrev 2012-08-30 01:37:
> OK, I'm confused. I always figured the car's speed was determined by
> final drive output speed, whether that speed was produced with or
> without O/D. IOW, if the final drive is producing 2,000RPM in straight