Big difference in price too. Plus with the 4" bore you can put the L92 heads on it. Car Craft did an LQ4 with L92 heads and got 550hp for less than $5000. They probably could have saved a little more if they had foregone the carb setup and did the L76 intake kit. Below is the two part story from CarCraft.com.
http://www.carcraft.com/projectbuild...ock/index.html
http://www.carcraft.com/techarticles...ads/index.html