fuel injunction questions
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From: conway arkansas
fuel injunction questions
i was just wondering if anyone has ever actually tried to put a small cam in an EFI 351, i have a 91 F-250 with 193000 miles and have developed a misss in it, i am pretty sure its a burnt valve but since i gotta pull all that crap off anyhow just to do a valve job i am gonna go ahead a put a fresh motor in it, any help with this subject would be greatly appreciated, i know that it is a speed density system but i am old fashioned in that i have never really messed with injection, always had a good ole carb
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From: Bartlett, TN
Well, if you decide to put in an aftermarket cam, keep a few things in mind. Speed density is not very forgiving when it comes to manifold vacuum. The less you have (under 20" @ idle), the more likely you are to get a surge. So, that being said, I would recommend something with a duration @ .050 less than 210, with about a 112-114 LSA. The lift is up to you, but keep it under say 0.475 for valve clearance. The biggest thing to keep in mind is that you absolutely must maintain 20" vacuum at idle in order to keep your PCM happy.
Sean
Sean
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From: conway arkansas
hey man thanks for the help, i got a cam here at the house i pulled out of an old 302 i just remembered that it is out of a 302 tho, dammit, wrong firing order anyhow, i guess that solves that problem,
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From: Bartlett, TN
Well, not necessarily. Depending on the 302, it could have a 351 firing order. The 302 HO (i.e. Mustang 5.0) used a 351 firing order. Plus, if the 351 is bank fire and not sequential, then you can just change the firing order on the distributor cap without any harm to the engine. However, if you're going to that much trouble, you might as well just buy a new cam for the 351.
Sean
Sean
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From: conway arkansas
well this is a lunati cam of unknown duration, it does have a monstrous lift of .455 and .468 i just figured it make wake it up a little bit, but i know for a fact that it does use the 15426378 firing ordre
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I know everyone is tired of hearing me say this:
Comp Cams has (2) Xtreme Energy cams and at least (2) Magnum Series cams that will work great with your Speed Density system--as is. LSA is kept at 114, with lifts up to .512. They have an on line catalog. Much info there as opposed to calling a tech. I can post the cards if you like...
Have some fun.
Comp Cams has (2) Xtreme Energy cams and at least (2) Magnum Series cams that will work great with your Speed Density system--as is. LSA is kept at 114, with lifts up to .512. They have an on line catalog. Much info there as opposed to calling a tech. I can post the cards if you like...
Have some fun.
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