There may be some more info on the 303 sohc developed by brabham. It was based on the 3 liter Buick based f1 engine he used in '66 and '67 which made around 350hp in '67. Brabham actually won both championships despite competition from Ford, Ferrari, Honda, Maserati, and BRM even though the repco-brabham was down 50-75hp, mostly due to dead on reliability and an extremely light car. Interesting that they could only get another 25hp with a 2 liter increase in displacement, though I suspect it was nowhere near finished. I believe that was not the only Pontiac engine produced by brabham, if you look on
www.repcobrabham.com, you can see the reference to it in their parts listing (740 series, 5 liter engine). The timeline seems about right, the prototype produced in 1967 before they worked on the raV and IV variants. May be worth a call or e-mail to them to see what block the 5 liter is based on and what it was used in, as they indicate they have some spares (though that might only be the 3 liters) and it was a 'production' engine (meaning they made a few for racing). If one of those could be pieced together you'd have one rare Pontiac. The FI system was most likely indentical to what was used on their f1 cars, and info and parts should be available. Doubt any of it would be anything approaching cheap.