CAM (smog)
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Senior User
Joined: Apr 2006
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CAM (smog)
I am about to put a new 400 w/edlbrock performer w/egr intake into my truck. I had planned on pulling with it(5000-10,000lbs). I really want a new cam to unleash some of that untapped power. Do you think I need it? I am in California and my truck is a 79' so I must pass a smog check. I am very scared of not passing. Can anyone suggest some options? I a have buttoned up the front of the engine, but I'll tear it apart if it is worth it. I really thank you guys.
79' F-250
400 C-6
4:11-4:56(tag is gone)
VIN# is wrong
I bought it from the widow of the gentlman whom built this truck, very nice work and parts, but no bills or paper trail
79' F-250
400 C-6
4:11-4:56(tag is gone)
VIN# is wrong
I bought it from the widow of the gentlman whom built this truck, very nice work and parts, but no bills or paper trail
Tuned
Joined: Jul 2003
Posts: 455
Likes: 3
From: Berkeley
i kick myself almost daily for not having gone with the CompCams 255DEH when i had my 400 rebuilt. I let the rebuilders pick the cam, and they put in a Melling MTF-2, which has similar specs to the edlebrock cam performer cam for the 351M/400 and is not highly regarded around here.
The 255deh is optimal for low-end torque, should suit your needs well and
should not be a problem for the sniffer.
your biggest worry passing smog will be the visual inspection. they want to see the static ignition timing matching the under-hood sticker, AIR pump and EGR equipment present (don't think they test to see if it works...). If your truck is classifed as heavy duty (F250 might be - depends on GVWR,) you may not need a catalytic converter (my '82 E350 doesn't). Headers are NOT a problem and neither is the Edlebrock 3771 aluminum intake manifold (with the EGR adapter plate). Technically, one should have the factory 2-bbl carburator and that's the limiting factor on top-end performance if you must stay smog-legal...
The 255deh is optimal for low-end torque, should suit your needs well and
should not be a problem for the sniffer.
your biggest worry passing smog will be the visual inspection. they want to see the static ignition timing matching the under-hood sticker, AIR pump and EGR equipment present (don't think they test to see if it works...). If your truck is classifed as heavy duty (F250 might be - depends on GVWR,) you may not need a catalytic converter (my '82 E350 doesn't). Headers are NOT a problem and neither is the Edlebrock 3771 aluminum intake manifold (with the EGR adapter plate). Technically, one should have the factory 2-bbl carburator and that's the limiting factor on top-end performance if you must stay smog-legal...
Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
Be sure to install a new timing chain with the cam timing 'straight up'. The factory timing set is retarded 4 degrees, and will reduce the torque at low RPM. As Packlet said, the Comp Cams 255DEH is the prefered cam.
Tuned
Joined: Jul 2003
Posts: 455
Likes: 3
From: Berkeley
i thought i had read somewhere (here?) that the 400's in trucks did not necessarily have the factory retarded cam timing. best to replace it anyways and make sure it's installed straight-up, but might not make for much power gain (other than correcting late/sloppy timing due to slack...)
Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
Originally Posted by packlet
i thought i had read somewhere (here?) that the 400's in trucks did not necessarily have the factory retarded cam timing. best to replace it anyways and make sure it's installed straight-up, but might not make for much power gain (other than correcting late/sloppy timing due to slack...)
Like you said it is a good idea to replace the timing set, especially if it is the factory set.
Postmaster
Joined: Aug 2001
Posts: 4,270
Likes: 5
From: Delaware
The stock valve springs should be adequate for a 255DEH cam. You should check the timing with a degree wheel to see if your timing set is retarded. If it is replace it along with the new cam, or even if you don't replace the cam. You should check the new cam with a degree wheel as well.
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