Will 0deg offset timing + 255DEH pass the Emissions test?

[ctubutis]

Hey, guys, I'm probably going to have a lot of questions and be asking for some
input on a possible (maybe partial) rebuild of a 400 but I'll try and break it down
to bite-size chunks.

The truck in question:

1981 F350 400 4x4 T18 4.10 31" tires Holley 4412 2V headers 2.5" true duals. I
live at 5300' and use this thing for hauling a few thousand pounds of firewood in
the wintertime, mostly along the Front Range of the Colorado Rocky Mountains
but I sometimes haul the same weight up in the mountains at around 9,500 ft.
so low-end power is important; the thing rarely gets over 3,000 RPM and I've
never had it past 4,000.

I want to install a Holley Truck Avenger 670 cfm + Edelbrock Performer 400 EGR
manifold this summer; because I also need a new timing chain, this might be a
great time to install one at 0deg offset + some sort of cam.

But, will it pass the smog test? If so, what cam would you guys recommend?
I've searched the forums here and it seems y'all like the 255DEH or maybe the
XE256H for these kinds of uses?

-chris
colorado, usa

[bareaneye]

The Avenger will NOT pass here in Oregon. I leaned, retarded, plug gapped only to be turned down. We are allowed 300ppm of c.o. and the lowest that I could get it was 480-500 ppm. If you need to pass an emission test, you'll need a carb with the emission diamond #1, which will pass, according to Holley. I ended up having to put cats on it to get it to pass. If your emission limits are higher in CO, maybe you can get it to work. Also depends on the condition of your engine
Craig

[hollenjoe]

why dont you pass the emmision tests and then change whater you want to change, keep your old goodies for later tests...

[ctubutis]

Originally Posted by hollenjoe

why dont you pass the emmision tests and then change whater you want to change, keep your old goodies for later tests...

That's honestly been an option I've been strongly considering; the thing is
25yo now and therefore qualifies for Collector plates, which means I can get an
e-test every 5 years or if/when I sell it.

Colorado's CO limits are 800; because I'm thinking of enabling the EGR & smog
pump (at least for the tests) bareaneye's experience suggests I might be able to
make it pass.

But, with what cam? And, can I do 0deg offset timing?

I for some reason don't want Collector plates, not until the thing looks halfway
decent; right now, it's a rusty POS but bodywork isn't gonna happen this year...

-chris

[graden]

I have that same engine combination and use a Edelbrock 600 carb....duel exhaust with a pvc valve....just lean the idle mixture screws a touch...passes every year here in vegas...below 500ppm

[bareaneye]

I have the same cam and gear/ timing chain. With a 570 avenger, and a wieand 8010 manifold, msd 6 ignition and dist, headers and flowmaster exhaust. When I did the cam, I also cleaned up the ports on the factory heads. I am not running the egr, maybe would have made a difference. It is a good idea to keep the old manifold and carb, wished that I would have done that. Here in oregon, emissions every two years. The cut-off here for no testing is 76' I believe. It would have passed with the factory pieces.