It's not necessary to replace the entire flywheel,
you just need to replace the "Ring Gear". You heat it up with a propane torch just enough for it to expand and it will come off, you can also flip the ring gear over and use the other side of it. When Tilton Engineering built the flywheel for my 478M to the dimensions of the 305E flywheel it was discovered that the GM 6.2 liter V8 Diesel uses the same ring gear as the 305E so that's what was used.
