Speedo and tach issue

[Phew]

So just swapped an 05 6.0 w/ trans into my 97 k3500. Ls pcm is reading the correct speed checked by my scanner compared to GPS. Speedo in cab is double at low speed and about 25-30 mph higher at highway speeds. Any ideas what it could be ?

Also tach doesn't work at all found the correct tach wire on pcm and truck but I get nothing at the dash, worked before the swap.

Any ideas would be great