recently picked up a 51 cranbrook. motor is tired and burning oil (valves or rings). I found a rebuilt slant 6 out of a late 60's that has never been installed (built about a year ago) with three speed trans for a sweatheart deal. any comments or suggestions on the amount of fab swapping will take? I have 10 years as a line mech, but have never done a custom swap job. any advice would be great! thanks