new exhaust

hey i just put a new fmf on the 426 but was made for the 450....fits perfect but notice more backfire on deceleration..is this the pipe or a possible valve needing adjustment????

The pipe could be a little loose, leaking exhaust. This is likely the cause if it didnt happen before.

Did you rejett for the pipe? Pop on decel after putting on a new pipe sounds like a lean condition. When you upgrade your airflow, you'll need to jet richer to make up for it.

run it lean and fry the motor:banghead:

The pipe could be a little loose, leaking exhaust. This is likely the cause if it didnt happen before.
:thumbsup: Check the header gasket and the mid pipe joint.

did not re-jet....header gasket and joint are sealed.....jet is stock what should i try for new jet??

did not re-jet....header gasket and joint are sealed.....jet is stock what should i try for new jet??

this can normally be cured by ritchening the pilot screw, if it does not stop popping on decel by the time you are at 3 turns out you will need a bigger pilot jet

I installed a white bro's carbon pro on my 06 and it popped like that. I raised the needle two clicks and installed bigger main. Problem fixed.

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