[Steve Barcak]

Poison Heart-
I think you may be interested in some Pontiac history here-
While I was not around at that time, I have studied and researched this subject extensively. Some of the senior gents here may wish to add as they were there...

Thompsons involvement with Pontiac went from 1959 ( possibly late '58) until Jan '63.
I say that because I have never seen or heard of anything with Thompson and '58 Pontiacs though he may have been involved in '58 for the '59 models. Prior to that, he was well known as a hot rodder, innovator and track manager. As an example, he is recognized as the first man to have a 'slingshot' dragster ( putting the driver behind the rear axle for better weight transfer and allowing better control because of position). Also, when the very famous LIONS drag strip in Long Beach opened in '55, Mickey was the track manager as well as a racer. I do not remember how long he managed Lions, I think about 5 years.
Prior to his involvement with Pontiac he ran several types of cars in drags and bonneville and probably more. he had a twin engine Hemi bonneville car around '56-'57.

Back at that time many automotive manufactures built and ran specially prepped cars for racing to promote sales. This included Nascar racing on the Daytona beaches ( this was prior to the super speedways), drags, land speed, endurance, etc. Pontiac was known as a dull but, reliable old mans car when Semon 'Bunkie' Knudson took over control at Pontiac in the summer of '56. He changed the direction of Pontiac that, generally, remains to this day.
Bunkie and Mickey were friends and he had a lot of respect for Mickey. At this time, M/T enterprises became the primary performance outlet for the performance/racing section of Pontiac. They worked closely together for those few years developing and testing performance and racing parts for Pontiac. Mickey was contracted by Pontiac and much money flowed ( my understanding is the amount was in the millions of $$) in his direction for racing and development. That was a period in Pontiac performance history that will never be equalled. At that time, Pontiac practially owned NASCAR winning well over half of all the races over all the over makes (Ford, Merc, chev, Dodge, Plymouth, etc ) COMBINED. By this time "59-'63, there were Nascar superspeedways. Pontiac and M/T also went for the absolute land speed record and clocked a 406 mph pass in 1960 using 4 blown Pontiac engines. M/T also smashed many standing kilometer and mile speed records with Pontiacs.
This wonderful relationship (Pontiac and M/T) lasted until Jan 1963 when General Motors corporation officially banned Pontiac from any and all racing involvement. This not only included building and designing parts and offering complete race cars ( SD Catalinas and Tempests) but, any involvent with racing at all, including contracting with the aftermarket including Thompson. The $$$ faucet was literally closed overnight. That was the end of involvement and all development or racing parts, offically anyway. Thompson did not remain loyal to Pontiac, he was a business man and went with Ford and stayed there.
There is more Pontiac history info on my site, with pictures, if interested and I encourage you to go there and read a bit. Look up 'history' page.
I hope this helps you understand why M/T was involved with racing Pontiacs and why it stopped.
Note, you will never hear of a factory 1964 Pontiac Race car or related engines or parts. Pontiac had enough sharp enterprising people to steer this performance 'roll' so to speak and restruture their direction and changed marketing direction to build and advertise cars from racing to high performance street (enter GTO) and it stayed that way until the end of the era.
as a side note- Arnie Beswick started racing Pontiacs just before M/T in 1958 and continued to race them after the 'ban' in '63 until 1972. This 'underdog' reputation contributed greatly to his popularity by staying with Pontiac while most all others abandoned and went to Ford and Chrysler who continued officially racing through the '60s.
The Jan '63 racing ban officially effected all GM divisions though chevy got their way for the most part. After Jan '63 the only teams that had official racing was Ford, Merc, Dodge and Plymouth. that is why you may hear of 'factory" race cars after '63....they were only Fomoco and Mopar.