This hobby is made up of basically three types of cars; restored (whether for show, or not); drivers; and speedsters. The last two types often have some modifications to their engines, as witnessed by the number of Z heads and Stipe cams, among other parts, that are installed. Some owners don't have the bucks to spend on fancy OHV heads, so the best 'bang for your buck' can usually be achieved with a high lift cam change; a oversize valve change; or a different manifold and carburetor change.
The following pictures are not numbered, but from the pictures you should be able to tell what is in each picture. The first picture shows a common T intake, a common A or B intake, and a high performance aluminum A/B intake manifold. The second and third pictures shows a common T and an 1932 Model B exhaust manifold. Notice how much bigger the B manifold is. The outlet of the T manifold slides up inside the B manifold with a loose fit. The fourth picture shows a T Holley NH; a Model A Zenith 2; and a Stan Howe rebuilt Stromberg OE-1 carb. The last picture shows the OE-1 carb with a 1927 Dodge Fast Four air cleaner that I plan to run. There are many options even if you don't have thousands for an OHV. Due to the size of the pictures, I may have to post them in two or three threads.