[bbcmudtruck]

If you have a standard bore block that will clean up at .30, go that route. No need in boring the block more than needed. Your not going to miss the difference between the 489 and a 496. If your starting from scratch, get ahold of cnc motor sports for a rotating assembly. They are truly balanced in house before shipped to you. Unlike jets or summit. Ideally, you'd want a 4.25 stroke crank, 6.385 rods and pistons to match accordingly. I prefer scat assemblys, but anything can be broken if abused! You'll need your rotating assembly before you take your block to the machine shop. Almost forgot, if it hasn't been mentioned yet, be sure to get an internal balanced crank. You'll need a neutral flex plate and 427 harmonic dampner.