I have a 406 pushing 500 HP and I passed the smog test with flying colors. The heads I have are 195 afr heads. Unless you have an old engine or problems with your fuel injection system you should pass. My CO-% was .36, HC-ppm was 24, and the NO-ppm was 229.check out my engine combo on my web site.link down below.
I have a crane cam it has alot of power.
119831
grind # hr-284-2s-12 IG
222.0-230.0 duration
509-528 lift
2500-6000 RPM
LOOK AT MY WEB SITE FOR THE REST OF MY MODS.
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www.geocities.com/camaro1j/myz28.html
406
accel supper ram
6000 rpm Hyd roller cam
afr heads
spohn torque arm and crossmember
t-56 trans, [wier racing bellhousing and hydrolic throwout bearing]
9" ME rearend 3.91 Gears