I have a 440-448 in the car now with a .557 cam, TF 240 heads, Victor intake. Has been a best of 10.49, but typically a 10.70's car. I have both 400 and 440 blocks. If I go the 400 route I'd need pushrods, intake and a distributor, which isn't a deal breaker. My gut tells me to go the 400 route since the blocks seem to be stronger than the 440, plus should be a little easier to work on in my duster. However at the same time, the 440 route would be a little cheaper and I would think that block would be fine for my power level, but I don't want to build it and down the road the block break and I'd second guess myself.