Stumpy, found your clutch post.
What Is 5/8 In mm? 15.875
15.875 x 30 mm = 23761.473214285692
3/4 in mm is 19.05 in your modded cylinder x 30 mm stroke = 34216.5214285714
7/8 in mm is 22.225 mm
Wilwood 7/8 dia, 1.2 inch (30.48 mm ) stroke yields 47317.64729999997
1 inch is of course 25.4 mm for our needs, I think the wilwood 1" is also 1" stroke which would be 25.4 x 25.4 = 51502.2011428571.
results are in cubic millimetres as per calculator at
http://www.online-calculators.co.uk/...ndervolume.php
If you have limited pedal throw go for the 1" type, will be a bit heavier naturally, 7/8" gives a good pedal and got the resistance I like. Some nissans had a 7/8" dia but not sure of the stroke I went for the known quantity. Getting sick of buying multiple parts/ running upgrades.
You do the maths. (facepalm)
been done for you