Will heads of a 2000 HP5OO carb motor gen6,,,fit on a 454 gen4 carb motor.

They say you can do it with the proper head gaskets but I learned a very expensive lesson. No it did not work. Water jacket mis-match was too great. Water leaked into the intake valley and runined lots of stuff.

K, that's what I hear too. it seems it is imperative that the deck's water jacket have a 1/2 inch min. of gasket surface, that is overlap mating area along the upper valley area in order to work. from what I hear 1 or 2 in 10 sets look OK !
cya soon

GenIV will fit on GenVI no problem. Gen VI to Gen IV is 90% of the time a big problem.

I use Mark IV heads on a Gen V block. Using standard Gen V gaskets. The strange thing is the holes for the water jackets on the gaskets are smaller than the openings on the castings. From what I have heard Gen VI head will not work on Mark IV block. Gen V and VI engine blocks are very similar. Other than Gen VI used factory dogbone roller lifters.