Jumping stumps is hard on the transom, the gear case, the prop, not to mention the owners nerves. Without power trim the engine had shock absorbers in the transom bracket along with the spring loaded latch. I always filed the latch so it didn't take as much to let the lock release. Never trusted it.
That engine is over 40 yrs old, and not a lot were equipped with power trim, lots had power tilt. The CMC is probably your best option, and allows you to transfer the Power Trim to another boat and/or motor