Might be one of those 1940's- 50's home built racers we used to see featured in Popular Mechanics Magazines.
Sometimes imagination usurps common sense and you have to at least try to build it. If it's a fail...nothing lost. If it's a success, you are a mechanical genius.
The rear crossmember looks to be model A ,or Ford anyway, I'd be nice to know what the bottom looks like so maybe we could i.d. the hood used. Most circle track guys don't streamline the bottom that I know of so maybe a Bonneville project because the hood is so rusted.
I think that it's really cool. You can see at the front how the top and bottom curved flanges are welded to the reshaped rail sides, and a neat little mounting flange welded to the underside to allow bolt-on of the inverted hood. I agree on Model A rear cross and likely front spring too, minus some leaves. I think the dagmar is 55 Buick.