I must interject here and give you , in my opinion a better option. A shortened 235 water pump does fit but not without it’s own possible problems. Doing so does not center the fan on the radiator for maximum cooling and might cause overheating on a hot day.
A better way to fix this interference issue is to purchase a water pump and fan for the original engine 216/235 from 1953, then use an adaptor plate to realign the pump to the radiator. This adaptor plate, designed and manufactured by one of our own bolters “Pre 68 Dave”, can be purchased from him directly by PM’ing him thru this forum.
I have a ‘52 3100 with a ‘59 235 and went this route. Fairly easy to install and you can hardly tell it’s not stock.
He has a website showing this adaptor plate. Here is a link.
http://chev235guy.blogspot.com/search/label/Water%20Pump%20Relocation%20Adapter
