First things first,

You must remove the old engine that's fitted and check the rails underneath as there's no point in changing anything if they are not in good order.

So please remove the engine and clean up the area with some petrol etc. and then take a good close up photo of the engine site around the mounting holes and post it up on here and then I can best advise you.

Cheers,
BB.

I live a 24 Hour lifestyle, but every now and again I seem to fall asleep, well at least that's what my wife tells me.