We're both right
"The original V10 was reportedly built with the involvement of Lambourghini, which was partly owned by Chrysler at the time; the basic engineering was of course Chrysler’s, since it was based on the venerable 360, but Lambourghini worked on the cooling system, crankshaft balance, weight reduction, and fine tuning; the Italian automaker’s expertise in aluminum was also tapped, since the Viper had an aluminum block to save roughly 150 pounds of weight."
