I have a flywheel that I pulled off a 454. I had assumed that it was a 350 flywheel, since they swapped in the 454 replacing a 350, and they had used a balance plate that was bolted between the flywheel and crank. I just had that flywheel re-surfaced to use on a 350, and I noticed 4 balancing holes drilled on the front of it. (left flywheel, bottom left of pic) Did some 350 flywheels have balance holes drilled in them like this? (the flywheel on the right of the picture is a 350 flywheel for sure).