is this If Clause correct?

[bromma]

Hello,

I'm not sure if this sentence is correct:

"The book should have had endless pages if it had to describe all the great things that you do".

Thank you very much for your help!

[tigerpaws]

This is a contrary to fact conditional. It describes an unreal, future situation, so you need to use "would". I recommend changing it to: "The book would have endless pages if it were to describe all the great things that you do."

[bromma]

Thanks a lot tigerpaws, I would never figured it out on my own!

[Raymott]

Thanks a lot tigerpaws, I would never have figured it out on my own!

If you need it in the past tense (if the book is already published), you could say:
"The book would have had endless pages if it described all the great things that you do."
"The book would have needed endless pages if it described all the great things that you do."

[bromma]

Thanks.

The sentence is what you would read in a book dedication.

[albeit]

Hello,

I'm not sure if this sentence is correct:

"The book should have had endless pages if it had to describe all the great things that you do".

Thank you very much for your help!

The sentence is correct, Bromma, but it's a bit unusual in the sense of uncommon. should in this case holds the same meaning as would. Sometimes should is used in this fashion to be more formal, more polite, more literary, ... .

I believe that BrE makes a far greater use of this should.