IMO, if it’s grinding you could have one of several issues or some of them or all of them.
Number one for grinding in 1 gear is an incorrect linkage adjustment. Just getting the pin through all the holes doesn’t mean it’s correct. Sometimes you have to make the rod a bit longer to get the adjustment needed.
I never, ever use stops on any shifter. Ever. If you set the stops so the slider is all the way onto the clutching teeth, what the hell do the stops do? I’m getting ready to install a Hurst Ram Rod shifter on my junk, and I remover the stops.
If you have a disc with the marcel in it (a thin, wavy spring between both frictions) you need more plate departure to keep the clutch from dragging. IMO, unless it’s your Honda or some other junk, the disc should never have a marcel. If you have a marcel, increase your plate departure. Even if you don’t have a marcel, you may need to increase the plate departure. I don’t recall what pressure plate your using, and I don’t want to go back and look, but if it’s a Borg & Beck I always had the finger height raised .100 to make it easier to get more plate departure.
Junk syncros. I’ve had brand new syncros that were machined wrong that would grind. IIRC the taper was wrong so there never was enough of the syncro to grab the gear and slow it down.