man if your running cats thats awefully restrictive for a 292 cam. Up where I am from we have what is called aircare....emissions testing....mine fails but there is a loop hole that enables me to avoid being tested.......mine is not a daily driver anyways but with that cam, 9.5 min...for compression ....and i would run at leat a 2 1/2" exhaust from the headers......sounds like your combo is toooorestrictive for any flow....you also might want to consider a higher stall as well.....292 cams are made for high rpm ......definately run a 3.73 gear.......but if you are running a tire taller than 27-28" might want to consider even a 4.10 gear.....the drive train should be matched proporly from rad all the way back to the rearend in order for everything to work proporly........hope this helps