I just pulled a camplate out of a LR 300 pump and it has a much less symmetrical profile that the one pictured. The UP ramp is much more steep. I replaced it with a Cummins plate because it had a few rust pits in it.
...BTW your Bieber avatar is awesome.-Malone
If you can use a mig welder, "Hey"'s posts in the FAQ are pretty much a step by step on building a mtdi pump.
libby = newish and support.. for 2x as much..