I'd go with the Surfers. Pretty minimalist.
Of course, if the manufacturer loved us, they'd include an Enderle injected SBC so's we could build a junior fueler if we wanted to.
If the manufacturer loved us.
How much undersized? The engine in the Ala Kart was a 1954 266 ci Dodge Red Ram. I think it was only 27" long? Maybe use it as a start to the Adams & Enriquez junior fueler?
One of my pet peeves about those great old flicks. Could also believe that the editor or producer believed that the audience (kids and teens) "wouldn't know the difference. I don't have the time or money to match stock footage - just get this picture out to the drive-ins!"
The engine was available with low-rise, medium-rise, or high-rise heads, and either single or double four-barrel carburetors on an aluminum manifold matched to each head design.