I agree with Corpt.

JFK is very much a case of luck and whether your flight arrives shortly after any others causing the immigration hall to fill up.

My last experience at JFK was not great. 1 1/2 hours in the immigration queue alone.

I also wouldn't do it. Would it be on a single ticket?

Good point by jmc1K, it is far quicker to get through immigration on a US passport at T7, highly likely to be less than 30 minutes.