The only aluminum was the crank case and heads on the corvairs. The cylinders were cast iron, just like a VW. The only silicon embedded blocks I know of was the pos vega, and the 928 Porsche. Never saw a 928 trailing blue smoke like a vega though! :rofl:
They could have updated to pass emissions, and 22 to 24 mpg with 4.11s and 31 inch tires isn't bad milage. Both of mine are smooth also, an inline 6 is smoother than a V6, that's why the Vs have ballance shafts.