You probably should have started a new post, Prairie Dog.
Welcome to Stovebolt.com.
"swapping out a 235 with a 270"
1. Into what make/year truck?
2. What year 235?
The later 235/261 engines have a water-pump that "sticks out" further that the earlier 216/235 water pumps.
This can be remedied.
Look in Tech Tips regarding engines.
But feel free to keep asking questions.
In each new thread/topic/question, be sure to indicate the Make, Yewar, and Model of your truck (and, describe pertinent modifications, if any).