I have all the parts now for the 3.42 Detroit Locker upgrade
3.42 is a really nice compromise gear. 3.31 is on the tail end of performance and 3.55 is getting a bit much for high speed highway driving (unless you have overdrive). It's a shame GM never made 3.42 for the passenger car 12 bolt diff.
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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles
1966 Grande Parisienne, 396 1 of 23 factory air cars
3.42 is a really nice compromise gear. 3.31 is on the tail end of performance and 3.55 is getting a bit much for high speed highway driving (unless you have overdrive). It's a shame GM never made 3.42 for the passenger car 12 bolt diff.
Interesting, that they didn't have it. But, agreed on the 3:42 for best overall - I changed from the 3:31 to 3:42 and it made all the difference by eliminating a slight lag in the OD (700R4)
-- Edited by 1965CS on Thursday 11th of March 2021 10:24:45 PM
The tensile strength degrades after theyre first torqued, but as long as they arent subjected to loads outside of typical street driving, reusing them wont be a problem.
If the engines been juiced, or the car will be track- or street raced, fresh Grade 8 bolts are cheap insurance.
-- Edited by see2xu on Thursday 11th of March 2021 09:58:02 PM