I have had my Merck. since it was 1 year old with the same Rear with No Problem when it was Stick I used to Race at the Drag Strip I Set a Record of 16 Second's in the 1/4 mil.back in 1962 & it took somebody 10 years to break the record. Now I Changed the engine & Trans to a 327/300 hp with a powerglide That was43 years ago, & i never had a problem with the Rear End The Last time I Checked the Ratio is 3.73 which i have lowered with Tires size Just my 3,5 cents Live Learn & Die A Fool