Frequency synchronization in GNU Radio for OFDM 16-QAM x 6

I am transmitting a 16khz data signal using OFDM 16-QAM x 6 carriers and the library amodem using a HackRF. However, I am having issues receiving this signal as the frequency the HackRF transmits on does not match the actual frequency, and the offset is not static.

I want to find the peak of this transmitted data signal through a given start and end frequency range and decode it. I think the best approach to do this would to be to "center" the HackRF on the peak of the signal through a given start and end frequency range. For example, if I was transmitting the data on 451 mhz, and my frequency range was 450mhz and 452mhz, I want GNU radio to automatically set the HackRF’s frequency to 451mhz and "lock on" to the data signal.