Ok the ezl is the ignition control unit mounted on the drivers wheelwell. It usually has a green wire ( but sometimes black) going to it from the crank sensor which is mounted on the bellhousing area on the drivers side near back of block. Anyway if you disconnect this wire at the ignition unit the car does not recieve fire cause their is no crank signal going to the control unit .That way you can spin the car over to build oil pressure after and oil change so you dont jump timing. On all older v8 motors dont go over 100k miles on the chain.ONLY use factory tensioner.I worked for an indi years back when I first started and they used aftermarket tensioners for a while . 6 out of 11 cars came back with jumped timing due to the tensioner failed . We called the others back in and put factories in all of them but only after we did 5 valve jobs and 1 engine job for free! I learned right off that you use factory stuff on alot of critical stuff on these cars .I have stuck with that since that day. On late model 119 motors I dont agree about the chains. If you change your oil every 3k miles like you are supposed to you wont have these problems. I have several customers who have 150k-200k on their 119 motors and we have checked for chain stretch with no problems found . On most late motors that have that much mileage when it comes time for any major engine work then I would agree to go ahead and do the chain then. The older ones are just a poor design and they will always fail after 100k miles no matter what.