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.
It looks that way. I had to do an edit on the post. The top of the chart was cut off.
seventy2plus2 said
Oct 21, 2023
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)
4SPEED427 said
Oct 21, 2023
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.
cdnpont said
Oct 21, 2023
2.29 not available with PG or LM1/L48.
Makes sense. Might be a old dog off the line without a BB.
ABC123 said
Oct 21, 2023
This car is a dream on the highway but the only way to know for sure is to pull the cover and check for numbers.
The car is totally unlike any other 69 I have driven.
I'll bet the cover has never been off.
seventy2plus2 said
Oct 21, 2023
Do you have the Protect-O-Plate for the car? If I recall the diff stamping is on there.
ABC123 said
Oct 21, 2023
seventy2plus2 wrote:
Do you have the Protect-O-Plate for the car? If I recall the diff stamping is on there.
Yes, somewhere, I will continue looking for it.
Thanks for the reminder !
I will find it Mark
LT1Caddy said
Oct 21, 2023
Jack it up, mark the driveshaft with chalk and turn the wheels...
65 SD L79 said
Oct 21, 2023
LT1Caddy wrote:
Jack it up, mark the driveshaft with chalk and turn the wheels...
x2
4SPEED427 said
Oct 21, 2023
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!)
CdnGMfan said
Oct 22, 2023
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
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.
It's too bad Vintage services never included this information.
As noted, you could order a different axle.
So it's a 3.07 by default with the PG?
Is it a 2.73 Randy?
Its interesting in the 1969 Impala specs it lists 2:73 as the economy option. Just think if it was a big block the economy option was 2:29!
-- Edited by Prefectca on Saturday 21st of October 2023 06:52:35 PM
2.29! Man that's high. BB wouldn't care.
The 69 B USA LM1 gets 5 more HP than the CP?
It looks that way. I had to do an edit on the post. The top of the chart was cut off.
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)
2.29 not available with PG or LM1/L48.
Makes sense. Might be a old dog off the line without a BB.
The car is totally unlike any other 69 I have driven.
I'll bet the cover has never been off.
Yes, somewhere, I will continue looking for it.
Thanks for the reminder !
I will find it Mark
Jack it up, mark the driveshaft with chalk and turn the wheels...
x2
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!)
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