When i start my 91' LB9 up first thing in the mornings it has a big white puff of smoke. I know it prolly a head gasket. How hard is it to change one and what should i do while i have the heads off?

 

i wouldnt say head gasket, i'd say leaking valve seals.

 

lot of questions from you huh? lol

most likey its your valve seals or valve guides. what happens is when the engine sits and cools down for a few hours the seals shrink, this lets oil slip by and ends up sitting in the cylinder. when u first fire it up the oil burns up and makes a white/blue smoke for a few seconds until the seals expand from the heat. if you have smoke when the engine is revved it may also be the piston ring seals. probably is not your headgasket as that will cause major problems that you'd be aware of but it could be the begining of a serious headgasket problem. check your oil for coolant and do a compress check on the cylinders if u think its the headgasket.