Difference between lt77 & r380

[sowen]

I've got a few 'spare' gearboxes kicking around the garage now, some are lt77, and some are r380. I've always read that the r380 is dimensionally near identical to the lt77 and a direct swap:



^ the lt77 is at the bottom of the picture above. It is from an sd1 and the r380's I have came from sherpa vans.

Is it normal that the clutch pivot pin and release bearing sleeve sit about 1" further forward on the r380, and would it still work fine with the standard sd1 type clutch bearing and fork, or do I need to source any specific parts to make it work? Or would I be better off shortening the sleeve and pivot pin to match the lt77 dimensions?

Simon