Ive googled to no avail, can anyone give me that axle ratios for a 412? Im assuming manual and auto would be different. Thanks
The 412 gear ratios are in the 412 OM pages 13 (auto) and 14 (manual). The differential ratios are quite different (1:3.25 auto and 1:4.30 manual), but the final drive ratio in the top gear are more similar (1:3.25 auto and 1:3.418 manual) because 5th in the manual is overdriven: Image Unavailable, Please Login Image Unavailable, Please Login
Yes, the manual is going to definitely feel more "peppy" in the lower gears, but once they picked the GM auto transmission (with a 1:1 top gear) they were really stuck going with a fairly tall differential ratio to keep the top speed up. For a US 412 auto, it would be no sin to go to a slightly lower diff ratio if the parts were available. Are you doing/considering an interesting and/or crazy project , or just working on a 412?
Nothing exciting unfortunately, just a speedo swap from a 412 into another car because of parts availability. I was looking at my 400 on the hoist yesterday however, It could use an extra gear and more displacement. A 550 engine with ITB's might do the trick.
