If you do have to bore it, PLEASE do your research on replacement pistons, get in touch with a piston manufacturer like Diamond ECT, a off the shelf rebuilders will put you in the high 7,low 8 to one compression,PLEASE listin.

1968 Charger COLD A/C Hilborn EFI
512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim
2020 T/A 392 Stock 11.79 @ 114.5