You mean you *ONLY* want it to count to 7? OK.
Wire all jam inputs low. Connect Q4 to via a diode to PE (pin1), (anode to Q4). From PE connect a 1n cap to Vdd and a 100k resistor to ground. That ensures count starts at 0 at switch-on.
At start, the 1n cap is discharged and pulls PE high. That transfers the jam inputs (0000) to the count. 1n charges through the 100k and takes RE low.
So under any circumstances, the count will start at 0.
Clock pulses will then count to a maximum of 7 (0111). The next clock pulse will take the count to 8 (1000) and Q4 will go high. That will take PE high via the diode and the counter will again be reset to 0 by the jam inputs.
I assume you want it the count to rotate to 1 after 7. If not and you want it to stay at 7, then take Q4 to CLEN instead of PE. that will inhibit further clocking.
I hope that helps.