standard exhaust manifold causing too much back pressure?
Posted: Sat Sep 08, 2007 8:49 pmafter checking over everything more than twice i have a funny feeling my car is coughing back out the carbs when i try to lower the idle to something reasonable is because the standard exhaust manifold is too restrictive combined with the cam overlap ,anyone had any experience with this, i only have the standard system on to get it rego'd then i have a complete system with extractors to go on, specs are ported head o/s inlet valves tighe 949 cam[295deg duration] single 45 dcoe , elec ignition, 60 thou o/s , unsure of comp ratio , am i looking in the right place or should i be looking else where ??? i don't have the exact idle rpm as i don't have a tacho atm but sounds high should have a figure tomorrow hopefully cheers for any help