Export brace and Monte Carlo bar

Yes, you can jack it up by the crossmember under the engine...those who have done it claim it doesn't hurt anything....the stock crossmember is rather thin wall steel, but if you spread the surface area across a full jack(not a scissor jack or a bottle jack) it should be ok...if not...its time to upgrade to a Z-Ray crossmember I guess. Your other option is to spread the shock towers with something like a port-a-power. I myself wedged them apart with a 2x4 during the restoration and then built braces under the fenders that replace the outer shock towers and tie the entire structure to tubing tied to the torque boxes and cowl...those braces now hold the shock towers where they need to be regardless of whether the export brace/monte carlo bar assembly is in place or not.

Also...the carriage bolts coming up through the shock tower caps...they are NOT set in place...the mounting points are slotted...you can move the carriage bolts along the slots to a degree, allowing you some amount of adjustment....adjusting the bolts on both sides may be enough to allow it to bolt on...take off the shock mounts and take a look.

My car sat with no front end for about 30 years and no radiator support for the last 15 of that. It had closed up over an inch. I borrowed a porta-power and spread it back out to install a MC bar and before I had it aligned. It did not really take excessive force to get it back where it needed to be.