complicated find and replace

Hello. I want to change a bunch of formulas in a column but it's very complicated.

Here is an example. I want to change

=SUM('ACTUALS summary'!AL115:AO115)*1000
to
=SUM(INDIRECT("'ACTUALS summary'!AL115:"&O8&"115"))*1000
by using a find and replace.

BUT even if I can figure out how to do a find and replace for that, it gets complicated because while the other formulas have the same pattern, they are slightly different.

For example, I also want to change
=SUM('ACTUALS summary'!AL116:AO116)*1000
to
=SUM(INDIRECT("'ACTUALS summary'!AL116:"&O8&"116"))*1000

What do you mean? The cells are adjacent, but the references are random (somebody hard coded them in).

I was trying to do it piecemeal. For example, starting with replace sum( with sum(indirect(" but it won't let me do that because it says the formula is incorrect and then doesn't replace anything.

Here is an example of the adjacent formulas.

=SUM('ACTUALS detail'!AM162:AP162)
=SUM('ACTUALS detail'!AM133:AP133)

The indirect makes it so that the AP section of the formula becomes dynamic (referencing another cell that is automatically updated.