My deceleration popping noise is due to a non-working anti-backfire valve. I disconnected and plugged the hose that goes to the exhaust manifold air injection rail and I no longer get the popping noise. The engine also seems to rev up and run a lot smoother but maybe I just like the fact that I am no longer getting the popping. Replacing it does not seem like an option (expensive, hard to find). I have the ABV off the vehicle. I tried testing it by blowing though the intake, then applying vacuum and the air continues to flow out the output. I am pretty sure this means the ABV is defective. My question is, should I desmog? I would like to have a clean running engine but I have a feeling I could have the motor running cleaner and more efficiently if I desmog. I dont need to go to the sniffer ever again. I have seen diagrams to desmog but are there any online guides that step you though the process? I have heard that to do it properly you need to re-curve the distributor and make some kind of adjustments to the carb. I have rebuilt my carb and I put in a HEI so I think I can handle this part. I have the 77 high altitude emmissions setup according to my Haynes manual (pg 90, Fig 3.106) I have done a search and I cannot seem to find a page that gives all the details and procedures. Thanks for any help or suggestions.