1) Chains do not last forever 2) Cleaning your chain You should take your chain off the car every week and clean it in some kind of solvent, diesel works well or solvent from Napa or any auto parts store. Steps to cleaning a chain Power wash your chain when cleaning the car Hang and let dry for a day Clean in solvent – diesel will work and let soak for a day Hang and let dry Reinstall back onto your car 3) Lube your chain – I try to tube my chains 2 or 3 days before race day and then I lube again on race morning. If you lube at the track the lube does not have time to penetrate into the rollers and that’s what makes a chain last 4) Do not use a laser to line up your chain – use a straight edge, I have checked too many chains that have been aligned with a laser that was off ¼ inch. The laser will not show you squareness. 5) Chain guides do not last forever 6) Check rear axle alignment – things get bent and that’s an easy way to tell if you got a problem starting somewhere in the suspension 7) Check motor mounts – always check the motor mounts for straightness after any crash 8) Chain Lube – I use chain wax, use something that will not sling off.
How to align your chain –
The biggest problem I see on people aligning their chain is – They don’t put their rear axles at ride height to align the chain. A lot of people align the chain with the axle sitting on the main rails, that’s wrong.
As the rear axle moves up and down it is also moving right to left because of the pan hard bar or Jacob ladder. The Jacob ladder does not move side to side as much as the pan hard bar.
So get in you car, have someone measure the distance between the lower main rail and bottom of the axle and then cut you some blocks that will fit, this will simulate the car at ride heights.
With the ride height blocks between the rear axle and lower main rail you can:

1) Align the chain 2) Set chain tension 3) Time the bircages 4) Square the rear axle