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I built a 350 stroker using a build plan from Mark Remmel for my '72 442 convertible. The exhaust is a true duals arrangement (without an "H or "X" pipe) so the LH & RH banks are completely independent of one another. The exhaust signal at the LH tail pipe is very "choppy", I can feel very distinct, individual pulses; but the RH tail pipe is much more smooth, can't feel the pulses like the LH side. I'm still dialing in the engine tune, and the idle is choppy with about 15inches of vacuum at idle; CR=10:1, aluminum heads, headers, cam card is below. It has a throttle body EFI from Fitech and is running a little rich so off-the-line acceleration is a bit sluggish but still pulls strong and breaks the tires loose on the 1-2 upshift. The LH muffler seems to rattle a little where the RH side does not, I'm running DynoMax Super Turbos. Could this just be a bad muffler or signs of bigger problems or engine tuning? This is my first, high-performance Olds build so I'm in new territory as far as my experience.
Triple check the firing order and do a compression test. A power balance test could also be done by checking to see if each cylinder is producing similar power. If pulses are felt in the exhaust it could be a simple misfire or hopefully not a leaking/sticking valve.
Thanks for the suggestions. I pulled the spark plugs back in January and cylinder#3 looked a bit fouled. Cylinder 3 is on the LH bank which has the hard exhaust pulse. What's the best way to check for a misfire? Bad plug wire? what else should I look for? Here's a pic of the plugs from January. I cleaned and reinstalled the plugs with a new O2 sensor and the car ran better but still not right.
