I know the answer to this question... for the 2V blocks. Basically, there is no difference (same head bolt pattern), but there is some difference in the timing chain tensioners. I believe to put a 4V on a 2V block, or vice versa, you had to use half of the 2V tensioners and half of the 4 valves ones. Other than that, I think you used the front cover to match the heads and had to do some ECU magic.
Again, that's for the 2V-4V, so take it for what it's worth.
Dan
I know the answer to this question... for the 2V blocks. Basically, there is no difference (same head bolt pattern), but there is some difference in the timing chain tensioners. I believe to put a 4V on a 2V block, or vice versa, you had to use half of the 2V tensioners and half of the 4 valves ones. Other than that, I think you used the front cover to match the heads and had to do some ECU magic.
Again, that's for the 2V-4V, so take it for what it's worth.
Dan
Sean Hyland has a good writeup in his book about the various blocks. He discusses cast iron and aluminum blocks, vintages (91 to present), different casting plants (Teksid from Italy, Windsor, and Romeo) and also the power levels that each block type can safely be built for. He also discusses aftermarket blocks (like the Sean Hyland race block), oddballs (Ford GT and front wheel drive versions), and methods to go to larger bores (3.70"). For anyone interested in going to larger HP in these engines, his book is interesting reading.