Is a bone stock 429 an upgrade to a mildly built small block? in The Garage Posted July 10 · Report reply There's no replacement for displacement.... and the torque of a big block will make the front of your shorts stick out. I had a 429/C6/9" in an Aussie Falcon years ago. Touched the towers, sucked gas but did it all with ease. With 2.75 rear it lit them up from a standing start in 2nd gear. But, unless you know what you are looking at most people won't realise it's not a Cleveland and so the cool factor is missing. For $6K I'd go with a 351 Windsor based motor, keep all the current hardware and swap it in on a Saturday.