Camed 390
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Camed 390
How big of a cam can a truck 390 with no major internal modification handle? The truck is a 73 F-250 4x4 with a C-6. The engine has a aluminum intake, Holley 4 barrel carb, headers, electronic ignition conversion, dual exhuast. How big of a cam can I go with stock valve springs, and how big with new valve springs? Heads are stock.
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regardless of the cam, the springs get weak over time.. you'd probably see a increase in power by swapping in a new set of springs alone... i read an article somewhere and they did just a spring swap and picked up like 15-20 horses and better overall response and performance...
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I was told by someone that in a 4x4 dont get a cam .495" on the intake side and that the 390 soaks up duration but no more then 290 advertised degrees and a lobe centerline of 112 degrees and do aluminum spacers in place of the stock rocker arm spacing springs do anything for valvetrain stability?
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Originally Posted by Cat man
I was told by someone that in a 4x4 dont get a cam .495" on the intake side and that the 390 soaks up duration but no more then 290 advertised degrees and a lobe centerline of 112 degrees and do aluminum spacers in place of the stock rocker arm spacing springs do anything for valvetrain stability?
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From: the side of a mountain
are you sure the engine is even really a 390? they never came in 4x4s. and if it is i would be willing to bet it doesnt have the compression a truck 390 had. it sounds like it has had some work done to it with the aluminum intake and headers.
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Originally Posted by piperig78
390's came in alot of 4x4's
Stock, that is.
(At least, in the '73-'77 range. I have no personal experience with pre-'73 pickups).
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Originally Posted by krewat
Nope, it was never a factory option. 390's are 2wd only.
Stock, that is.
(At least, in the '73-'77 range. I have no personal experience with pre-'73 pickups).
Stock, that is.
(At least, in the '73-'77 range. I have no personal experience with pre-'73 pickups).
!["Beemer Nut"'s Avatar](data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 50 50'><circle class='avatar-circle-default' fill='%23bc5285' cx='25px' cy='25px' r='20px'></circle><text class='avatar-text-default' x='49%' y='53%' fill='white' text-anchor='middle' alignment-baseline='middle'>"</text></svg>)
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From: "Islander"
On post #4 why do you think people add alumimum spacers instead of springs?
A **** poor design from day one to leave anything to chance like springs. When a 390 gernades at 5,800 all because rockers walked over against springs instead of solid spacers it's a no brainer.
.....=o&o>.....
A **** poor design from day one to leave anything to chance like springs. When a 390 gernades at 5,800 all because rockers walked over against springs instead of solid spacers it's a no brainer.
.....=o&o>.....
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From: "Islander"
I run FPP roller rockers that came with spacers purchased 20 years ago.
Not a clue about after market spacers alone as I haven't been looking.
Maybe other members will chime in.
If I had to I would make my own as I have a lathe.
.....=o&o>.....
Not a clue about after market spacers alone as I haven't been looking.
Maybe other members will chime in.
If I had to I would make my own as I have a lathe.
.....=o&o>.....
Last edited by "Beemer Nut"; Jun 28, 2006 at 01:46 AM.
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From: "Islander"
I wouldn't use springs if the motor never went above 3,000 rpm's, want to build on chance? Do the airline mechanics repair on chance or leave maintenance until another time? Want to fly on chance? Get my drift, but then it's your motor.
.....=o&o>.....
.....=o&o>.....