Looking to replace Indirect function to pull dynamic ranges

[Jordan4412]

I've created a dynamic range formula which shows as below:

=CONCATENATE("AC SalesRawData!",SUBSTITUTE(ADDRESS(1,C1,4),"1",""),":",SUBSTITUTE(ADDRESS(1,C2,4),"1",""))

Which gives me the range output "AC SalesRawData!CQ:DS"
I'm then referencing this range in an vlookup using Indirect as shown below:

=VLOOKUP($A7,INDIRECT(C$3),'AC Sales Conversion'!C$4,FALSE)

The issue being, there are thousands of this formula pulling individual pieces of data. I don't want this to recalculate all the time as it keeps kicking errors or returning #REF!.
Is there a way to replace the indirect function but get the same result?

 

[Cubist]

What is the reason you're using INDIRECT currently? Can you post some mockup data?