Hi everybody I have a 83 camaro z28 it has a 74 350 motor bored 40 over with 10 to 1 pistons 194 valve heads rollerrockers ,crane cam 290 dur 496 lift 104 lobe seperation pro form geardrive eldelbrock performer rpm intake 600 edelbrock carb , headers,3000 stall converter 350 turbo 373 gears with a spool no computer no converter built just the way they use to be in 69 my problem is i was sitting at a red lite and the rpms dropped from 850 to 600 when i took off the engine feels like its running on seven cylinders i pooled the plugs and they all are black sooty they use to be the color of chocolate milk i took the carb apart checked float levels sprayed carb cleaner through every hole checked and cleaned disrtibutor cap wires nice blue spark on every wire checked timing 14 initial 34 total vacume at 850 is 10 to 12 inces i checked all vacume lines by pulling them one by one the only thing i know to do is try another carb any one ran into this before or have any suggestions?