If they sell the 5.00 inch crank then what motor would it fit. Being a tall deck you'd think you could get a longer stroke in it than the standard deck. I guess it just dosent make sense to me. Sorry if I bug you I have a lot to learn about a big block. And did you mention donivan heads? what are those. Also my buddy just put together a 396 and they said it had to idele at 1200rpm because the came is rated from 1200 to 6000 or so.