BTW, there is no direct fit adapter to bolt the 4500 to a 235.
You are correct that there isn't a direct fit adapter. There is an adapter that will work with a little bit of machining. The adapter plate is indexed for the later(1968 on) truck bellhousings. Those bellhousings are indexed to 5.125 inches. The 235 bellhousings are indexed to 4.686 inches. Any competent machine shop could chuck the adapter in a lathe and turn down the indexing lip of the adapter plate to fit the 235 bellhousing.
So in summary, the adapter plate is made that will fit the 1948-1967 chevy and gmc bellhousings, but it requires a little work.
