[olddog]

The 302 (5.0 ltr) engine from the factory in all cast iron is around 400 Lb or 180 Kg.

You can get an all aluminum engine by using aftermarket parts. I think Ford racing even lists aluminum blocks. I'm guessing that should drop 1/3 of the weight and get it down to 120 Kg. If I was going that route, you can up-size from 4.0" bore to 4.125" for the same price. That gets you about 363 cid.

If you do not need to keep it that light, you can go aluminum heads and intake on a cast iron factory block.