If your engine is still in the crate and the balancer still on, you could try sharply striking the end of the breaker bar with a big hammer/wood block.

Thanks again for the tips. A brief update...

We've decided to leave the balancer on for the time being. If there's a problem with it down the road, then we'll address it, but the motor is rather new in terms of mileage. Figured out that the newer engine had the fuel filter mounted along the left side of the block - after removing its mounting bracket, the mounts worked.

However, what impact will this have when the 87 filter is all the way back by the tank? I am wondering whether or not that is the usual location or if someone managed to relocate it somehow.

Thanks in advance,
Nick