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Just a few general questions- My 69' Coupe has a 3.70 axle (according to the code).
Were ALL 3.70 gears posi or did they actually have 3.70 open ends in 69?
At 60 MPH, I rev at 2750-2800 RPM in 4th with P225/60R15 tires. Does this sounds about right for a 3.70 gear?
I was expecting it to rev somewhat higher.
Thanks!
Elm.
Were ALL 3.70 gears posi or did they actually have 3.70 open ends in 69?
At 60 MPH, I rev at 2750-2800 RPM in 4th with P225/60R15 tires. Does this sounds about right for a 3.70 gear?
I was expecting it to rev somewhat higher.
Thanks!
Elm.
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Send PMFrederick, MD - USA
Joined: 9/8/2003
Posts: 3398
Vette(s): 1969 convertible L71 427/435 4-speed black interior
Posi-trac was a $46.35 option with all axle ratios in '69, and the vast majority of Vettes were so equipped (36,965 out of 38,762 Corvettes total).
Your rpms sound pretty normal to me. My '69 has a 4.11 rear and at 60 mph I'm turning somewhat over 3000 rpms with P215/70R-15 tires.
Your rpms sound pretty normal to me. My '69 has a 4.11 rear and at 60 mph I'm turning somewhat over 3000 rpms with P215/70R-15 tires.
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Send PMHot Springs, AR - USA
Joined: 4/24/2004
Posts: 3236
Vette(s): 69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans
at 3.36 i run 3000 @ 72mph
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Lifetime Member
Send PMHot Springs, AR - USA
Joined: 4/24/2004
Posts: 3236
Vette(s): 69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans
http://www.5speedtransmission.com/gear_calculator.html
this link says you should run 2915 RPM @60 mph
a 3.55 has 2797RPM @ 60 mph
could a PO have swapped it ?
question for you though..
why the small tires ??
|UPDATED|6/24/2004 2:17:49 PM (AZT)|/UPDATED|
this link says you should run 2915 RPM @60 mph
a 3.55 has 2797RPM @ 60 mph
could a PO have swapped it ?
question for you though..
why the small tires ??
|UPDATED|6/24/2004 2:17:49 PM (AZT)|/UPDATED|
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Since the car is 35 years old, the possibility of the gears being swapped at some point is very likely.
The carrier itself is for the 3.70 but until I either open the pumpkin or start counting turns on the driveshaft, I won't know for sure.
If it's anything below a 3.70 (numerically), I would have to seriously consider either swapping the gear or going to an M-20. My off the line kick, even with the ZZ3 motor, is somewhat disappointing.
The P225/60R15's are plenty big for my use. If I can't turn these puppies over now, why go any bigger?!
The carrier itself is for the 3.70 but until I either open the pumpkin or start counting turns on the driveshaft, I won't know for sure.
If it's anything below a 3.70 (numerically), I would have to seriously consider either swapping the gear or going to an M-20. My off the line kick, even with the ZZ3 motor, is somewhat disappointing.
The P225/60R15's are plenty big for my use. If I can't turn these puppies over now, why go any bigger?!
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