The stock Quadrajet on my 1978 350 has no idle mixture adjustment screws! I didn't notice this until I'd already gone to the trouble of cleaning the carb, bolting it onto my new manifold, and adapting all my linkages, etc. It runs fine, but I'm sure I could smooth out the idle a bit more if I could rich it up just a teeny bit. There are just silver metal plates filling the round holes where the screws would normally be. Are these just covers? If I pry them off, will I destroy my carb, or will I find adjustment screws patiently waiting for me to adjust them? I DID try to search to see if this has already been covered. If it has, please just post a link to the old discussion. Also, I know that a 1978 Quadrajet isn't exactly "traditional" and don't need anyone to remind me. The entire running gear in my '53 Chevy is from a donor car (1978 Impala wagon = CHEAP), and I'll take "cheap" over "traditional" any day. You wouldn't believe how many parts you can use off of one good donor car!