First, get the conversion kit that converts the mounts from pin mounts in the front and bellhousing mount and changes it to the side mounts. A number of companies make headers for the swap, Hooker has a set. Not sure oabout firewall clearance on the HEI, might have to rework the distributor notch in the firewall a bit for clearance. Also, if my feeble memory serves me correctly, the radiator has to be mounted on the front side of the radiator support... Not a real tough swap as long as you get all the right parts.