question about new headers

sa6988

New Member
Jul 5, 2004
13
0
0
Chico,CA
i just put in some mac equal length headers in my 5-0 to complement my off road H and flowmaster mufflers..but ever since the headers were installed a weird thing has happened. (my car is an automatic) where the car shifts into the next gears has changed....it doesnt even get out of 1st til around 40mph...and the rpms never red line or anything like that so how is this happening? is this bad? please give me an explanation...if i didnt give enough info please ask. thanks a lot

oh and the car shakes a whole lot now while idling can that be minimized?