Customs 1955 super 88 Oldsmobile rim and tyre size

Hi I'm looking to get some rims and tyres for my 55 super 88 my question is how big can I go on the back 235, 245, think I will go 7" 225 on the front its lowered 2"

 

btt

 

i went for 7" 225 55 17 lucky i didn't get bigger it would have been a problem

 

Gotta be careful on the rears, must be able to take one off in case of a flat. My 235/75-15 tires just make it.

 

yeah the wheels i took of were 235 75 15