I have heard that some newer wheel cylinders have built in residual valves or something that makes the valve unneeded.
If it was me I would look for a proper replacement, or see if you can get a valve and seat and install in the mc.
ALSO ..
my research shows that the 1" mc for the application has been out of production for some time. Used or NOS are the only options. Not even rebuild kits.
There are 15/16 and 1-1/32 masters available