I recently converted my 65 Malibu SS 250 HP Powerglide to the 350 HP L-79 option. After bolting it all together and starting it up I can only get it to idle down to about 1000 rpms before I run out of adjustment. I had never used the carb before. I purchased it used and had it rebuilt and replated at Jones carb in Huntington Beach CA. Could it be a intake maniford gasket leak. I used the new kind that do not require gasket sealer.