8 1/4 rear questions

From the factory they made two styles of sure grip,the cone style that most older stuff has & then there is a clutch style that showed up later on & it was the bic lighter of clutch diff's not as strong @ holding power as the cone style is. Also i cant remember what year for sure they changed the spline count from 27 to 29 on the axles. They also therw in an 8 3/8 ring & pinion somewhere other than R&P all else will swap ex. carriers that were 2.45:1 & higher wont swap with 2.94:1 & lower.