[Keithc8]

You are not going to do a 4.600 bore on a block that has 4.640 bore center. You would have a wopping .040 between the cylinders and it would last no time. You can move the sleeves out in an aluminum block but then you have heads that are not centered on the bores, piston not centered because the crank is made for 4.640 bore.
This would be one big as problem pain in the ass. Why do it when you can uch better with less cubic inches or go to a 485 series 460 engine. If you go much longer then a 4.500 stroke you get crappy rod angle, short compression distance pistons and more problems.
I even feel that the 580 C.I. engine is not worth the money or trouble and you could make more power with a smaller better designed engine. It amazing how many FE gurus there are suppose to be but how many have made over 900HP with a normal aspirated wedge head FE engine, not many. with the parts that are out now you should be able to make 1000HP with the right normally aspirated FE engine but how many want to pay not many.
Till you get a block, crank, heads and all done with a wider bore spacing you are just pissing in the wind on anything much over 540C.I on an FE engine and I would not go that big if I was buidiong the best HP combination. ENOUGH MONEY YOU CAN DO ANYTHING. You also take some of these guys that have money and they think they can, but it takes a combination of money and know how.
You will find that there are engine gurus every where. I know I talk with them ever day and they have not made the first chip or machined ****. They bolted some parts together.

Good luck, Keith Craft