gt40 heads i can get stock on an explorer along with all the serpentine front dress radiator and condensor along with aluminum driveshaft(which is the correct size for the mustang with a t5 conversion) and disc brake limited slip rear end. pretty solid setup since my mustang has a mustang 2 front suspension already and i can use the low location of the ac compressor due to no shock towers. gt40 heads are the best cast iron head ford ever made for a sb. i can get a whole explorer for 500 and aluminum bare heads would be well over double that then add valves etc etc. im not looking for the fastest mustang. just a quick one that won't break the bank to build.