I've been continuing to drive the Blazer the past couple months and it's really running nice. I finally corrected the speedometer, which has been waaay off since I bought it. It was reading 40mph when I was going a GPS-indicated 60. I also knew that 2500 RPM was ~72mph
I used this page to figure out my rear gear ratio --
http://www.angelfire.com/fl/procrastination/rear.html -- turns out I have a 2.73 rear gear. No wonder this thing is kind of a slug.
Once I knew the gear ratio, I went here,
http://www.5speeds.com/calculators/SpeedoCalc.html and figured out which speedo gears I would need. Tony had a few speedo gears from when he changed his, but didn't have the right combination. I ordered up a 9 tooth drive gear and 18 tooth driven gear from
https://transmissioncenter.net/shop/drive-gear/
But, no job ever comes out perfect. There's a little metal tab that holds the speedo-bullet in the tailshaft housing and it was missing, or so I thought I had ordered the little tab when I bought the speedo gears, but when I went to put it in, I discovered the bolt that holds it in was broken in the tailshaft housing, not just missing. And of course, I didn't find that until I had already put everything back together. I'll tackle that another time. It's stayed in this long without it, I'll tackle that another time.
But the good news is that the speedo now reads perfect. $50 for both gears, the speedo bullet, the metal tab and shipping. I probably didnt need the bullet, but bought it just in case. Money well spent.
Tonight, I decided to take it out to the dragstrip instead of the Chevelle. I've been wanting a baseline number in case I make some improvements. The forecast was for warm weather, and potential rain, and I was feeling lazy about changing tires on the Chevelle, so it was as good a night as any. I got several compliments on how it looked, which was nice. So, the good news is that it's at least faster than my dad's Mustang, but barely. My best of the night was a 15.72 @ 89 MPH with a 2.29 60-foot. I can't get the shifter down into 1st gear, so it shifts at 4000 RPM 1-2, and I'm crossing the line at about 4300 in 2nd gear. I got 4 time runs in, but lost in the first round. I tree'd the guy (.1 to .21), but I hit the brakes at the the last second. He ran 13.67 on a 13.66 dial, so he was right on. I went 15.90 on a 15.75 dial. Being my 5th run, I was happy to go home early to watch the Cavs/Raptors game #5 in the Eastern Conference Finals. Cavs are crushing the Raptors, beating them by 40pts late in the 4th qtr!
-Dave