Camshaft choices

[KMK172008]

What exactly are the choices i have for my 98 4.0? i have headers, glasspacks, and the 99+ intake. I'm looking for rough idle.

the other thing is: will i loose power braking at low rpm? my friend says i will

[Dr. Dyno]

If you want a longer duration cam to increase higher rpm power and produce a lumpy idle the trade off is a loss of torque at lower rpm, less vacuum at idle, and less vacuum for the brakes.
I suggest you keep the stock cam, port the head, and add a set of Yella Terra 1.7 roller rockers to increase valve lift and take advantage of the ported head's higher airflow.

[KMK172008]

already ported and polished the intake. roller rockers i haddnt considered though

[5-90]

The power freed up by rollerised rockers would be minimal - the advantage is that they'd have a 1.7:1 ratio, vice the 1.6:1 that the OEM stamped rockers have. This would slightly increase valve lift (not duration - that's a function of camshaft lobe profile.) Still, it would help to increase airflow, by having the valve open more, if not longer.

[KMK172008]

those roller rockers are 400$. no thanks, ill just buy a cam and press the brake pedal a lot harder

[gradon]

I have good feelings on Clifford, Isky, and Mopar cams(I'm currently using a 30ab). Do some research on advancing cams as well(esp if you don't plan on going in the 4Krpm range much).

[Dr. Dyno]

those roller rockers are 400$. no thanks

Yeah but they're shaft-mounted and will make the valvetrain much more stable than the stock pedestal-mounted rockers. I have the 1.6 ratio "yellow terrors" in my stroker but I also have the stock '92 cam which has 0.424" of lift and stock valve springs (rated to 0.430" lift).

[Sherman_thetank]

go with a custom ground lunatti voodoo....they set me up with one for a turbo on my fresh rebuilt...the dyno software claims it would make 375hp and 425tq! with only 5lbs of boost...so they know what their doin

[KMK172008]

my jeep is on hold right now as i build my 400 sbc for my 78 camaro. the next item i buy will be nitrous. the cam and roller rockers will be much later, as in maybe a year from now

[alex22]

The power freed up by rollerised rockers would be minimal - the advantage is that they'd have a 1.7:1 ratio, vice the 1.6:1 that the OEM stamped rockers have. This would slightly increase valve lift (not duration - that's a function of camshaft lobe profile.) Still, it would help to increase airflow, by having the valve open more, if not longer.


We have actually seen an engine loose a number or two from switching to a roller rocker arm (engine dyno). Their main purpouse is durrability and strength so you can run a larger cam with a stronger spring.
You might want to contact CamTechniques or CamCraft about a grind.

~Alex

[badron]

shaft-mounted and will make the valvetrain much more stable than the stock pedestal-mounted .
==================================================
At very high RPMs and with very stiff value spring. Else at sub 5k RPM a fresh OEM set up works fine.
Plus with a little work a pedestal mount will work well until say 6.5 maybe 7. It's not cheap but a lot less then shafter.
Stock and near stock cams have a lot of lift now. Much more then when special rockers with increased ratio first came into play. It is VERY possible that 1.7 would give you little more then bragging rights.
ALL THIS IS ON A STOCK OR NEAR STOCK HEAD/ENGINE.
Duds are pumping 1500 into special parts and seeing 30~35 extra HP. Not a good bang-per-buck payback in my book.
Force air induction
NOS
Big bore and long crank or a 4.7
Is the way to go. (IMO)

[KMK172008]

I'm putting my 350 that's coming out if my camaro in the jeep. The 4.0 will soon get to taste a 250 shot of nos. so I can run 11's.... Once