From das US forum
'VQ35 long block including intake manifold, no accessories - 313lbs weighed on a recently calibrated auditing scale with supposedly accurate to within +/- 0.5lbs'
So 142kgs, does that sound right?
Sqee you won't get massive muscles unless you go on roids and hit the weights big style.
Protein might help but I would suggest good diet will do just as well.
If you really want to part with your hard earned, then try myprotein.Com