The beauty of the Gen III/IV engines is that, like their Gen I cousins, parts interchangeability is what makes the world go ’round. Let's say you found a used, iron 4.8 or 5.3L truck engine for a budget price. The 4.8L (293ci) uses the same bore but shorter 3.268-inch stroke crank compared with the 5.3L. The 5.3 shares the same stroke as the 5.7 but with a smaller bore. So the trick is to machine the 5.3 iron block from 3.78 to 3.898 inches and add a 5.7L rotating assembly. Start by searching eBay or Craigslist for a used 5.7L Camaro or Corvette engine rotating assembly that includes the pistons, rods, and crank. Try engine builders like Lingenfelter Performance Engineering (LPE), Street Legal Performance, Turn Key, or others that do 383 conversions on LS1 engines and ask about their leftover rotating assemblies. These can be purchased for $300.00 to $400.00. We'll finish this idea in Part II.