I have unfortunatly found out my engine is nailed ,and to be honest it was probably done by the previous owner who im sure new.But i have had to deal with it and have got a very low milage replacment engine and charger.(the later type)Unfortunatly my big valve ported head was cracked and useless and so as i dont have the money to buy another decent performance head at the moment i wounderd if any one can tell me what extra power gains you get from a works/gp head as ive been offerd one cheap and could stick that and my high lift cam in it to try and gain some power back.Or are these heads pretty much stock ,if so i'll save my money and get a better head later on.The rest of my mods are listed below on my signiture.