As said because it is normally aspirated just use the block you have, it would be a lot cheaper to get the power out of your pinto than buy a cossie engine etc.
HT RACING(nr Brands Hatch) do these pinto's all the time, ROLAND HAYES, is the man there who is a genius with these heads and others, this amount of power does not need a cossie head to reach it.
Yes a cossie head will fit on, but will be a LOT more expensive way around, just use +90" pistons(V6) for 2080cc for a good base.
I would use 3d management for the ignition, as it will be lights years better than other stuff.
tabetha