The HP post previous got me looking at the specs, and surprised I see that my 69 Parisienne 350/250 with the powerglide should have a 3.08.
I coud swear that it was a 2.73 as the car cruises along the highway no issue at 80 mph. No tach, but she feels like she's not working too hard at that speed.
10 bolt or 12 bolt?
A 10 bolt ratio is 3.08, 12 bolt is 3.07.
What does the stamping on the front of the passenger side axle tube say? (assuming no one has changed the gears or diff)
My 69 Grande Parisienne 4 door hardtop 427 LS1 with air conditioning was built with 2.56 and I see in the chart that makes sense. Great diff, that 427 had no trouble with it. I pulled it out when I scrapped that car and put the diff in my 67 Grande Parisienne 396 wagon (also had air conditioning). Great combination, that 396 pulled over around 22-23 mpg on straight highway drives with the 2.56.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
I don't even do that any more. I just crawl under, mark the driveshaft, mark the bottom of the tire and watch the driveshaft while I do one full tire rotation. Even less effort (senior citizen thinking!)
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
The L65 (250 horse) & LM1 (255 horse) were the same engine except for the intake & carb. The L65 was the base Pontiac V8 for '69 & came with 10-bolt rears. The LM1 came with 12-bolt rear on manual cars & used Muncies rather than Saginaws (unlike the L65).
When the 327 was dropped from the Camaro during the '69 run, the L65 replaced the LM1 as the optional non-SS engine, & the 307 became base.
When the 327 was dropped from the full-size Chevrolet models late in the '69 run, the L65 became the base V8 & the LM1 was dropped.
3.07:1 rear ratio = 12-bolt 8.875" ring gear
3.08:1 rear ratio = 10-bolt 8.125" ring gear
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67 Chevelle Malibu Sport Coupe, Oshawa-built 250 PG never disturbed.
In garage, 296 cid inline six & TH350...
Cam, Toronto.
I don't judge a man by how far he's fallen, but by how far back he bounces - Patton
