Smaller, polished aluminum velocity stacks for a 4bbl carburetor.
Pack contains 2 stacks, turned solid aluminum, so there's no seam.
The stack is hollowed-out, leaving a solid bottom. You could drill it out so that you'd be able to see the carb butterflies.
Outside diameter at the carburetor junction is .21" (13/64")
By Parts by Parks, 1/25 scale.