Two questions (170 engine)

Is the noise more of a drone? Like a strong bass note ( harmonic )?
What kind of muffler did you put under there? glasspack? :)
That can be caused by a tail pipe that stops under the car or exits out the side in front of the rear wheel or a unusually long run of larger diameter pipe under the car (greater than 16 in length and about 2.5-3 inches diameter)


I'd have to STRONGLY agree with the fuel line mod, I'm in FL and even during the "winter" months I had the boiling fuel problem. I'm even testing a heat shield under the carb to keep it from experiencing hot start issues

Two different symptoms are caused by fuel that is too hot:
1. Drivability problems caused by the fuel boiling on the way to the carb (usually in stop and go traffic)
1a. The fix is the fuel line mod (move the line away from the manifold)

2. Hot start/flooding is caused when the fuel boils in the carb after sitting for 5-15 minutes. sometimes accompanied by black or dark brown sludge appearing around the orifices and seams of the carb
2a. The fix is a heat shield between the carb and manifold and/or plastic carb spacer to keep the heat from the manifold from bleeding up to the float bowl. The fuel line mod helped this a little but did not completely remedy the issue for me.

I've done the fuel line mod and now the line is cool to the touch when running, but let it sit with the hood closed after a short trip...the float bowl will burn your fingers