Those Boss blocks are suposed to be very decent. I think it is definately comparable to a Dart block. If you run over a 3.25" stroke, you have to run a special piston. However, the Boss block is the only 8.2" deck height block that you can run a 3.50" stroke crank on.
I'd stay away on principle. Custom pistons just to get the most out of a brand new block? Poor design. No thanks. There is plenty of information on the shortcomings of this block on this forum and Hardcore5.0 if you do some searching.
i'd have to agree with Adam. i've read too much about it to really say its worth the price. i'd rather invest in a dart block. now if a used one came up for a good price then okay but i couldn't justify a new one.
Eh. I spent a long time talking to Ford about the block. Basically they cut the skirts shorter to fit a 3.5" crank in there. I wouldn't call it a poor design, it's just not as practical as some of the other blocks. It should work fine.