I bought this to experiment with the Gotoh 510T-FE1 bridge on my custom Sully 625 and was successfully installed last night. My bridge is the version that comes with the FST mechanism.Observations:- This block is noticeably heavier than the FST block. Expect a few extra ounces of weight to be added to your guitar.- It fit my bridge plate perfectly. Definitely make sure to get a block that matches the string spacing of the bridge in question. This one is 10.8mm spacing.- The ball ends of the strings actually stop near the bottom of the block instead of near the top at the bend point that reaches the saddles. I'm reminded of the tremolo block on the Fender Eric Johnson models. String changes should actually be easier as it'll be easier to aim the strings into the block as opposed to something like the FST Mechanism where the guide holes are further down into the tremolo cavity.- As the ball ends stop lower in the block, string tension is also increased slightly. To put things in perspective, a set of regular 10-46 strings feel more like 10.5-48 in comparison to my old block. If non-FST Gotoh blocks have their ball ends stop at the same point, there shouldn't be any change in string tension.- There is a slight, but noticeable difference in the acoustic sound of my guitar. It sounds a bit more lively with some extra highs in the electric sound. My guitar already sounded great before; this added a little extra brightness. It's by no means a night and day difference. Manage expectations accordingly.Installation is overall rather simple: remove the strings, remove the saddles, unscrew the old block, screw in the new block, replace the saddles. All mounting screws are included. If saddle placement isn't marked before removing them, expect extra time to be spent with re-intonation. Intonation is honestly going to be the worst part of the entire install, and even that is easy compared to working on a Floyd Rose style bridge.There are variations of this block available in Musiclily's store. Compare the measurements to the blocks you're looking at with the measurements on your own bridge as well as Gotoh's dimensions documents for each bridge before proceeding.