Engineering requirement for block strength

We are bidding a job where the project engineer is requiring a 2500 psi block to meet an f'm of 1500 psi. We know that the new code allows a 2000 psi block to have an f'm of 2000 psi. What can we do?

Lets be clear, the project engineering can call for any strength block they desire - as long as it is called out in the project specs that are bid with the job. So if your project specs call for a 2500 psi individual block strength and an f'm of 1500 the 2500 wins and that is what you need to supply to the job.
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On the other hand, if the specs ONLY call out for a masonry unit that meets 2000 psi f'm they MUST accept the current code and accept a 2000 psi individual unit strength. Requiring a higher strength unit than is required by the code, and not called out in the bid documents, would constitute a change to the project.