Hey I have an 83 capri with a full 86 drivetrain swap (came like this)
I have always had a slight stumble/pop at idle and recently I upgraded to a mini starter so the headers off, also took the time to install a wide band, anyways I started the car sounded fine still the slight stumble at idle but revved up and such okay, I decided to re set all of my factory rockers thought maybe something was too loose. Now a couple of days later I've got what sounds like an exhaust leak but it seems to be coming out of the right side header, still pulls pretty steady vacuum so i don't suspect a valve sealing issue but off idle to about 1500 rpm engine seems to stumble. Not sure what to think, timing is 14 degrees btdc, plugs are new and wide band says about 12.5 ratio at idle. Let me know what you think. I have videos but not sure how to post them

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