I was leafing through a 1969 HOT ROD magazine and came across an article about the year's LSR competition at the Bonneville Salt Flats.
In the article was a photo of 4 cylinder powered belly tank lakester.
The caption stated the racecar was powered by a Pontiac Tempest 4 cylinder engine with a custom made twin cam cylinder head designed and built by Arnold J Birner.It was sometimes referred to as the "pepper tree Offenhauser"
Engine was de-stroked to 180 cubic inches & initially was boosted with a GMC 471 roots type supercharger.
Birner built more than one engine and the cars they were in were capable of and were clocked at top speeds well over 200mph.
This was all done with NO Pontiac factory support and on a low budget.
A later version of the engine was turbocharged & placed in a stretched wheelbase , front wheel drive stream liner.
I did some digging /sideways searching on the net and unearthed a small historical treasure trove of info on the car (s),engine & it's inventor
See the attached PDF.