Tansmission, rear survey
08-15-2006, 07:39 AM
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Tansmission, rear survey
I am just curious. How many 66-67 427/390 cars do members have with the original combination of the M20 wide box and a 3.08 posi rear? My 67 was ordered that way and it is a pleasure to drive. It is like having a 3.36-3.55 in first gear and then able to cruise at highway speeds comfortably. It is the only way to go.
08-15-2006, 08:09 AM
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2023 C1 of the Year Finalist - Modified
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That is the combo in my 56, but of course, that's not what came in it. I agree 100% that is the way to go today, ESPECIALLY if you drive the car out on the road as well as because of today's gas prices!!!
08-15-2006, 12:44 PM
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3.08:1 and wide (2.5:1 low gear) ratio - the way mine left the factory.
PS That's 7.7 turns of the engine per wheel rev
as opposed to 3.36:1 with 2.2 low gear for 7.4 revs.
The 3.08/2.5 combo put down more torque in low than the 3.36/2.2 combo that I am told was the default with HiPerf solid lifter cars. IMO that's why a lot of people with 3.36 gears say they don't want to go to 3.08s. They probably have the 2.2 low gear (providing less torque than a 3.08/2.5 combo switch would provide) and think the swap would mean less torque. Gotta do the math.
PS That's 7.7 turns of the engine per wheel rev
as opposed to 3.36:1 with 2.2 low gear for 7.4 revs.
The 3.08/2.5 combo put down more torque in low than the 3.36/2.2 combo that I am told was the default with HiPerf solid lifter cars. IMO that's why a lot of people with 3.36 gears say they don't want to go to 3.08s. They probably have the 2.2 low gear (providing less torque than a 3.08/2.5 combo switch would provide) and think the swap would mean less torque. Gotta do the math.
Last edited by magicv8; 08-15-2006 at 12:55 PM.
08-16-2006, 12:21 AM
#8
Ran a 3:55 and 2.5(m20) for 75,000 miles and thought it was perfect. Blew rear and dropped in a 3:08 and it wasn't as bad as I thought - it was also good for seriously long burnouts
First gear launch with a 3:70 with a close ratio 2.2 is not too different than a 3:08 with wide ratio 2.5 = first gear final drive ratio 8.0 vs 7.7
a 3:55 with wide ratio (2.5)box is 8.9 I seem to remember the new vettes I think are @10.0 in first gear??...................
I always thought the close ratio box was designed for 3:70 gears and larger, and wide ratio box was for 3:55 and smaller (numerically).
First gear launch with a 3:70 with a close ratio 2.2 is not too different than a 3:08 with wide ratio 2.5 = first gear final drive ratio 8.0 vs 7.7
a 3:55 with wide ratio (2.5)box is 8.9 I seem to remember the new vettes I think are @10.0 in first gear??...................
I always thought the close ratio box was designed for 3:70 gears and larger, and wide ratio box was for 3:55 and smaller (numerically).
08-17-2006, 10:30 AM
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The way the racers looked at in the 60s, was: the Muncies with the 2.5 low were for road (racing) cars that mostly used high gear, while the ones with the 2.2 low were for dragstrip machines - because their fairly equal gear spacing allowed the engine to jump between gears from the end of the power curve plateau to the beginning of the plateau in the next gear - otherwise referred to as "staying on the cam".
08-17-2006, 11:04 AM
#10
Melting Slicks
Originally Posted by tentuna
3.36 and an M20 in a 327/350 great combo
