LeMans rear drive ratios

[dxhall]

The stock 7/33 rear drive in my 1990 LeMans is badly worn.  I have an 8/33 gearset on my shelf left over from a swap years ago.  Has anyone run an 8/33 in a LeMans 1000?  I’m thinking about putting the 8/33 in the old housing.

[guzzisteve]

OK, I ran an 8/35 in my LM3. If you have a housing made before they started using the 8/33 you have to have some webbing cut out around the pinion gear. The old boxes(loop, 850T) have room, T3- 93's have webbing in the way.
I had a machine shop do the work.  Hey, then you can shift into 3rd at 100mph

[mtiberio]

According to my gearing chart, a 7:33 with a 120/90x18 rear tire will give you 140 MPH at 7750 RPM. Its possible a breathed on motor will pull that. With an 8:33 and the same rear tire, your bike would go 160 in 5th if it could pull it. It takes something like the Bill Ross's Mandello Meteor Land Speed Bike to pull those kinds of numbers. Does that mean the gears wont work, of course not. Expect to have to slip the clutch a bit more off the line. FWIW, with the 8:33, your 4th gear will be just about the same (138.4) as 5th with the 7:33 (140.3). Think of your bike as a 4 speed, ignore 5th, and you will hardly notice the difference.