cam+poping question
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Freshman User
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cam+poping question
ok guys i need a little help plz i resently had a 400 rebuilt from top to bottom all new parts runs good it doesnt have the power i want it to have i lose speed when i start to pull a little hill.
Specs.
Cam is a little bigger than stock sorry not sure about specs
ever thing else is stock outside of headers and exhaust
i would not have a problem pulling the cam and installing a new one if i had a good idea that it would make a good improvment.
ok about the poping it runs good every now and again it backfires through the carb when i get on it i thought maby water at first but after 2 tanks with heat in them still no change any ideas.
Thanks for your help ill reply to any post as soon as possible.
Specs.
Cam is a little bigger than stock sorry not sure about specs
ever thing else is stock outside of headers and exhaust
i would not have a problem pulling the cam and installing a new one if i had a good idea that it would make a good improvment.
ok about the poping it runs good every now and again it backfires through the carb when i get on it i thought maby water at first but after 2 tanks with heat in them still no change any ideas.
Thanks for your help ill reply to any post as soon as possible.
Lead Driver
Joined: Feb 2003
Posts: 8,140
Likes: 4
From: Oak Harbor, OH
What kind of carb did you use? intake? It could be the carb needs to be tuned, or the timing could be off. Check the firing order first, then check the timing, get ahold of the place that did the motor and ask them what it should be. They should have the cam specs, and proper timing for it.
Fleet Mechanic
Joined: Oct 2003
Posts: 1,371
Likes: 10
From: Green Springs, OH
I agree with 79 ts sounds like it is too lean, If it only does it when you accelerate hard from a stop it is definitly too lean, fatten it up a bit. A 400 according my specs is supposed to be set at 12 btdc. That is what I currently have mine set at and it runs great.
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ok guys sorry for not repling in a while i had to go outta state for a bit. yes intake a carb are stock intake is off an ltd and the carb is off my old 400 outta this truck carb had be rebiult i know the firing order is right as i was there for most of the prosses of droping the motor in. i asked the guy what size cam it was and he said he would try to find the specs for me it was just a friend that did this for me as i was outta state working ok ill try adjusting the fuel. the carb was completly rebuit like 200 miles ago when i got the truck back. as for timing i beleive he said it was set at 3-4btdc. but i could be mistaken ill find out. ok thanks for the input.
Ben
Ok i got one more question egr valve do i have to have it or can i block it off i have no emissions laws.
Ben
Ok i got one more question egr valve do i have to have it or can i block it off i have no emissions laws.
Last edited by mbburchell2004; Dec 22, 2004 at 03:34 PM.
Postmaster
Joined: Aug 2001
Posts: 4,270
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From: Delaware
If you block off the EGR, you will have to rejet the carb. The carb jets are set for the proper mixture with an EGR, without the EGR the mixture will be too lean. Best bet is to keep the EGR.
The headers will reduce back pressure and lean it out as well. You should get a couple of set of jets and try to go richer.
A nice Edelbrock Performer carb and manifold will help as well.
The headers will reduce back pressure and lean it out as well. You should get a couple of set of jets and try to go richer.
A nice Edelbrock Performer carb and manifold will help as well.
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ok thanks so if the egr isnt working it will cause problems i will try to get a set of jets as soon as possible so if i was using using flowtech headers and glass packs will the back pressure causes this also a friend told me the power valve in the carb can cause this any one agree thanks for all the help.
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Postmaster
Joined: Aug 2001
Posts: 4,270
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From: Delaware
Yes, the power valve can cause problems. It would be worth replacing. That is why I prefer an Edelbrock carb, no power valves.
You should really go to a 4 barrel carb and intake. You can find intakes on Ebay all the time.
You should really go to a 4 barrel carb and intake. You can find intakes on Ebay all the time.
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ok thanks only problem with that is that im on a teen budget but those will be the first things i do is a intake and carb. I had a 500 holly on it and it wouldnt run the carb wouldnt stay adjusted. thanks
