Mickey Thompson was another legendary racer and engine builder under contract by Pontiac. Mickey set the world speed record in his 4-engined Bonneville racer ("Challenger 1"
back in the 50's, and he also was heavily involved with Pontiac's drag racing program in the early 60's. In fact, Mickey received many of the rare SD421 cars in 1962 and 1963, and wreaked havoc on the dragstrips across the country.
He also developed some very interesting high-perf parts for Pontiacs. His cross-ram and 2x4 intakes were stuff of legend, but he also made some high end parts for Pontiacs. Before the 1964 Chrysler Race Hemi made its debut, and 2 years before the 1966 Street Hemi would hit the streets, Thompson built on Chrysler 1950's Hemi design and built Pontiac Hemi heads for the 1961-1963 389-421 Pontiac engines. Along with those heads, he built blower manifolds, and a host of other racing parts, even aluminum blocks, for Pontiac. The M/T designed Hemi heads were 100 hp stronger than factory Pontiac heads, and Thompson produced over 700 hp in race trim.
When GM's 'no-racing' mandate was passed down in 1963, Thompson went on to sell his parts independently. A lot of M/T Hemi heads were sold, and many still exist today.