69 Z/28 Day II Project (Air Force Brat)

[Chuck_Burg]

I have a 496 going in my 67 with a standard close ratio M22 with a 2.20 first and 28" tires. I'm in a similar boat to you, not really concerned with driving it on the highway for sustained periods... Not sure which gears to go with. It is a street/strip car with 90% street use. I think 4.11s are ideal but will blow the tires away on the street in probably every gear. May go with something around 3.55 even though the first gear will go forever... What are your thoughts?

[NorCam]

Originally Posted by Chuck_Burg

I have a 496 going in my 67 with a standard close ratio M22 with a 2.20 first and 28" tires. I'm in a similar boat to you, not really concerned with driving it on the highway for sustained periods... Not sure which gears to go with. It is a street/strip car with 90% street use. I think 4.11s are ideal but will blow the tires away on the street in probably every gear. May go with something around 3.55 even though the first gear will go forever... What are your thoughts?

Chuck, that 2.20 first gear with 3.55 gears and 28" tires will have a final ratio of around 7.80 which is going to pull the engine down when you let go the clutch. Granted your 496 is going to have more torque but there are much better transmission gear ratio combinations for street cars that will also see some highway use. (See the AGE gearing options here)

To keep it fun off the lights with 28" tall tires, I chose to run a 2.99 first gear. With the stock 3:73 rear, this should have a final ratio of 11.15 and will feel like having 5:13 gears off the light. Granted it will be a short shift when driving normally, but at WOT this should keep a good set of sticky tires running on the ragged edge until 2nd gear is pulled at 50 mph. I'd then pull 2nd gear at 4500 rpm and 3rd/4th would keep me in the 5200/5300 range on a full pass.

Best part is I get all the excitement of a great rpm launch that won't pull the motor down and will still have the final gear ratio of 3.73 for the highway runs in 4th. I may even choose to step down to a 3.55 rear gear when I rebuild the diff. That would have me in the 10.6 final range which is even more ideal. With big block torque, you could even go 3.31 and still have a better transmission ratio to easily launch the car without pulling the motor down off the line. Plus it's way more fun launching like it has 4:88's.

Might want to look into the gearing options here and check the multiplier on trans gearing x final ratio.

[Ryan1969Chevelle]

Originally Posted by NorCam

Chuck, that 2.20 first gear with 3.55 gears and 28" tires will have a final ratio of around 7.80 which is going to pull the engine down when you let go the clutch. Granted your 496 is going to have more torque but there are much better transmission gear ratio combinations for street cars that will also see some highway use. (See the AGE gearing options here)

To keep it fun off the lights with 28" tall tires, I chose to run a 2.99 first gear. With the stock 3:73 rear, this should have a final ratio of 11.15 and will feel like having 5:13 gears off the light. Granted it will be a short shift when driving normally, but at WOT this should keep a good set of sticky tires running on the ragged edge until 2nd gear is pulled at 50 mph. I'd then pull 2nd gear at 4500 rpm and 3rd/4th would keep me in the 5200/5300 range on a full pass.

Best part is I get all the excitement of a great rpm launch that won't pull the motor down and will still have the final gear ratio of 3.73 for the highway runs in 4th. I may even choose to step down to a 3.55 rear gear when I rebuild the diff. That would have me in the 10.6 final range which is even more ideal. With big block torque, you could even go 3.31 and still have a better transmission ratio to easily launch the car without pulling the motor down off the line. Plus it's way more fun launching like it has 4:88's.

Might want to look into the gearing options here and check the multiplier on trans gearing x final ratio.

I vote figuring out gear ratios for these old cars!!! My drivetrain selection is very similar to yours, 2.98 first gear, 3.42 rear gears, and 26.2” tall tires. Awesome SLR (starting line ratio)

The gear spacing is extra wide and feels a little much, especially at some downshift situations.....

Ryan W31

[Chuck_Burg]

Originally Posted by NorCam

Chuck, that 2.20 first gear with 3.55 gears and 28" tires will have a final ratio of around 7.80 which is going to pull the engine down when you let go the clutch. Granted your 496 is going to have more torque but there are much better transmission gear ratio combinations for street cars that will also see some highway use. (See the AGE gearing options here)

To keep it fun off the lights with 28" tall tires, I chose to run a 2.99 first gear. With the stock 3:73 rear, this should have a final ratio of 11.15 and will feel like having 5:13 gears off the light. Granted it will be a short shift when driving normally, but at WOT this should keep a good set of sticky tires running on the ragged edge until 2nd gear is pulled at 50 mph. I'd then pull 2nd gear at 4500 rpm and 3rd/4th would keep me in the 5200/5300 range on a full pass.

Best part is I get all the excitement of a great rpm launch that won't pull the motor down and will still have the final gear ratio of 3.73 for the highway runs in 4th. I may even choose to step down to a 3.55 rear gear when I rebuild the diff. That would have me in the 10.6 final range which is even more ideal. With big block torque, you could even go 3.31 and still have a better transmission ratio to easily launch the car without pulling the motor down off the line. Plus it's way more fun launching like it has 4:88's.

Might want to look into the gearing options here and check the multiplier on trans gearing x final ratio.

Good advice! I think I'll go with 3.55s and the current set up initially. If it lugs too hard in first, I'll go with the wide gear set in the AGE M22. I've never owned a car with this kind of torque (other than a magnuson superchargerd 2016 LT1 Camaro, which was just stupid) so I'll see how it goes... I don't think street tires will stand a chance even with the 2.20 first gear and 496 torque.