I'd stay w/ the '62 Unibody if it's in any kind of good shape. There aren't too many of them around, and you can do alot w/ them. I have a '62, not a unibody, and I'm now installing a 455 Olds and TH 400 in it. I've had it f/ about 24 years and I like that not too many people have one this year, and the unibody is much more unique. You'll be glad that you kept the Unibody. Good Luck.