I looked at a couple of sites and one said that the 4 barrel for a 265 was a Rochester.

Here is a list of carbs for Chevy applications for trucks from Carbking's website. I really only know enough to point you in his direction.
You can contact him through his website if you have further questions. Hope this helps.

http://www.thecarburetorshop.com/Trchevrolet.htm

"Nothing astonishes men so much as common sense and plain dealing." - Ralph Waldo Emerson