Removing Fenders for motor swap?

['70 C/10 SS500]

I'm very close to starting the motor swap from I6 292 to 500ci Caddy motor. I currently have the grill, bumper, head light assemblies, battery tray, and inner fenderwells removed. My question is: Is pulling the fenders and radiator support off to have an easily accessable frame to fab up the motor mounts worth the fitment issues with re-installing the fenders? I've PULLED fenders before, but never actually put one BACK ON! Is it all that hard. Should I remove 'em, drop the motor, and worry about the fitment later? Give me some good advice so I can act this weekend!

Hopefully soon it'll be nothin' but

Thanks!