The rear spring rate seemed a little soft and the rear was still sitting a low even after 2 inches of preload. I calculated the effective rate based on the shock mounting offset and I’m only getting about 55% of the actual spring rate. To achieve my target of 325lb rear rate I had to upgrade to heavier springs. I installed a set of 550lb springs and with 1″ of preload the ride height looks perfect.

I ordered a set of used Audi axles. The plan is to cut the Audi axles in half and mount them on the inboard side, then cut the GM axles in half and mount them on the outboard side. I’ll use a tube to sleeve the axles together at the correct length. Once the axles are put together and I confirm there is no binding, I’ll take them off the car and have a custom axle fabricated using my inboard and outboard CV joints. I was quoted $600 for a set of axles.

I ordered silicone hoses to complete the cooling lines in the rear between the firewall and engine.