This is my first post here so bare with me, I have a 78' Bronco with 400 and it actually runs really good but it was using a lot of oil when I bought it. Because it was a hunt/fish I put oil in it and let it ride. I found myself driving this thing daily when the engine on my work ride let go. So, it smokes on start up and I find myself constantly adding when needed. I have to change or clean spark plug on #5 cylinder about every 2 to 3 weeks because it is fouled and had to replace a bent pushrod in the same position about 2 months ago. Other than that it runs great and seems to have plenty of power. How hard is it to replace the valve seals on this thing seeing I am fairly sure where my problem is, or am I looking at a very costly rebuild? All assistance greatly appreciated. By the way - nice site!