Help please with connecting flight

Please can anyone advise on the below...
On 6th June I will be arriving from Vegas into JFK to then pick up the return to the UK. I have 2 G's booked from JFK back to LHR on 6th June departing 21:30. (No G's available from LAX/SFO/LAS back to UK)
I have 2 options:
LAS to JFK - depart 08.35 and arrive JFK 16:42 (nearly 5 hrs stopover)
LAS to JFK - depart 10:45 and arrive JFK 19:00 (approx 2.5hrs stopover)
Both on American Airlines - arriving JFK terminal 8
I then to have get our bags and get to Terminal 4 - is the second flight cutting it too tight on time??
Does anyone know how long it takes to get from Terminal 8 to 4
many thanks
Ollie
On 6th June I will be arriving from Vegas into JFK to then pick up the return to the UK. I have 2 G's booked from JFK back to LHR on 6th June departing 21:30. (No G's available from LAX/SFO/LAS back to UK)
I have 2 options:
LAS to JFK - depart 08.35 and arrive JFK 16:42 (nearly 5 hrs stopover)
LAS to JFK - depart 10:45 and arrive JFK 19:00 (approx 2.5hrs stopover)
Both on American Airlines - arriving JFK terminal 8
I then to have get our bags and get to Terminal 4 - is the second flight cutting it too tight on time??
Does anyone know how long it takes to get from Terminal 8 to 4
many thanks
Ollie