I don't understand your posts. What revision motherboard do you have currently and what Agnus is installed? You may already have one that supports 1MB.
Edit: look on the chart on Wikipedia or any of the other sources. Without looking myself I'm about 99% certain 8371 and 8375 are not pin-compatible. You can't just replace one with the other. You need an 8372A. (unless you want to rewire one of the sockets)