Slow 1/8 with 74 440 dart

If it's running a 2+ second 60 ft, without spinning a tire, thats where I would look for a solution. With 4.56 gear, and traction, that should be at least a 1.75. Save 2.5 tenths off the 60, and you'll be .75 quicker at the quarter, at least a half second to the eighth.
I don't know about solid sevens, but I would sure expect very low eights out of your combo.
There is a serious case of missing power, somewhere.