Speedo Pinion for a 4.875 rear

[mgslayer]

Does anyone know if there is a speedo pinion for a 4.875 rear? The parts car I picked up last summer has an H190 LSD with the 4.875 gears.':twisted:'
I know that my 4.11 gears will fit, but......... if I can find a speedo pinion that will work:
1- It has to be easier to switch the entire rear out than disassemble and reassemble 2 rears as a winter project
2- It will give my Beast even that much more punch off the line, I'll just lose some at the top end.
Is the 4.875 rear too much for a street car? When it's all back together the car will be a "daily driver", mostly on the weekends, but I do have dreams of Auto-Xing again. It didn't seem to be a problem going from the 3.70 rear to the 4.11.

Thanks

Mark