I installed a LT1 cam last weekend, and have been fine tuning it since then. Yesterday me and a friend were going to advance the timing. Well while I was hooking up the timing light, I asked him to loosen the distributor bolt. Well he loosened the bolt, and proceeded to turn the distributor as far as he could push it, for what reason you ask, I don't know. Well I'm not sure it really matters when the car is off, so I try to move it back to around the area it was before he decided to move it all around. Well I ask him to start the car, and hear a sound like someone took a hammer to the underside of my driver's side valve cover. A very loud "POP!" So I try to fix the timing a bit more, and it starts this time,with a clicking sound under the driver's side valve cover. I finally get the timing to 8* (after he moved the distributor, and we finally got the car to start, the timing very really retarded, an inch or two away from 0) and the car starts fine and runs fine. With no power whatsoever, but it starts and got me to work. But it was much faster with my peanut cam. Any ideas what that huge pop sound was? Thanks

 

Probably had nothing to do with the timing.

I'd suspect a broken valve spring or rocker arm.

In case people ever wonder why I (as well as other people, who are experienced) recommend replacing the stock garbage valve springs and getting rid of the stock rubber rockers any time anything is upgraded in an otherwise stock valve train....