Blows Main Fuse at 1/4 Throttle???

Check around the linkage to the tranny too. There may be something shorting to the linkage when you put it in drive. I would almost bet it is mechanical interference somewhere by the symptoms described. Good luck finding the short. You also said it happens in nuetral. What about in park?

It is a 4spd, I will check it out for sure. The only wire there is the Reverse Light harness which is also Brand New.