R/T diff install ?

[John Scott]

R/T mount, in my case ended up being slightly lower than my MSA solid mount. I mounted the R/T bracket into the chassis, perfect tight fit, GM mount already installed loosely. Picking correct length bolts which pass through the diff and bracket and running them up, not down, might eliminate grinding the crossmember for bolt clearance. Once in place and all other diff bolts tightened, I tightened all the bracket and mount bolts, the top center mount bolt above the bracket being the hardest to access due to the proximity of the handbrake linkage. I installed, or should say compressed, a new stock rubber underneath due to the lack of hard tested testimonials using the upper only. The new system is great for under power, but I worried about the energy suspension mount failing under repeated nose down forces, braking, downshifts. There are some on the site with outstanding mechanical engineering, racing experience credentials, but until they give their OK, I'll keep the bottom attached as well. In my humble ignorant opinion, the cross section of the energy suspension mount doesn't seem to have a lot of metal or urethane to solely support the diff under harsh conditions.. Maybe puttering around it would last for ever? The R/T design addresses the under power nose up force nicely, but I assume the forces pulling the diff nose down could equal or be greater than under power. The urethane mount wasn't intended to hang, especially with additional material removed to conform to the nose of the diff. Anyway, by comparison its much quieter than my solid mount, though sanwiched as tightly as I do might conduct a bit more noise than a stock rubber only. I guess I feel better about having a slight amount of flex under power and hard downshifts, should be better for the long term durability of the lower crossmember...right? The R/T system with the GM Energy suspension mount works great as a pinion snubber and if it could be finally tested under long term, high power drag and road course abuse, might prove to be the best mounting system for the early Z diff.