If I search for " 1929 Chevrolet Engine Parts" I get everything but that.
A search using those keywords will match any listing that contains all of those keywords anywhere in the title or item-specifics.
A search is only as good as the data that sellers provide, and the keywords, filters and category choices that a buyer uses.
Since there are many sellers in the automotive category that include spam keywords -- including all years between 1924 and 2024 -- in the item specifics of all their listings, it is often necessary to exclude a random year or a random make or model that is entirely unrelated to your search to avoid all those listings.
Try limiting your search to the Engine Parts category, and use some filters to limit your results to used items and Chevrolet brand parts (unless there is another name brand for your specific parts).
Try something like this as a starting point:
https://www.ebay.com/sch/i.html?_from=R40&_nkw=1929+Chevrolet+-1977&_sacat=33612&_sop=10&Brand=Chevr...
