Is it worth installing one of those Mopar performance cams in a 4.0 with allmost 80K on it? If so, what else needs to be taken into acount? Will I need to run high octane? I searched and couldnt find any specifics on stock applications just strokers.

thanks

the stage III cam will piss off the computer. not enough vacuum.
you are aware you basically need to rip a 4.0L down to the bare shortblock to install a new camshaft, right?

I am waiting for my buddy to finish my swap. But he is rebuilding my 4.0 with a new clifford cam. It is going to add 30-40 H.P., but i can't really tell you anything else about it (exceprt it only cost $200 for the cam) untill i get it back.

let us know how things workout. thanks and good luck

Know this: any alteration of any of the components of the Mopar MPI 4.0L will have a negative effect on performance, one way or another. It is set up pretty much optimally at factory settings. Anything you do to 'hot rod' the engine will have an effect. If you bore out the cyls (.060", like i did with my 4.2L block), the injectors can't quite keep up with the size of the combustion space. I have a perpetual lean burn (and subsequent miss) at idle with the injectors wide open at +30 (as measured with the DRB-II). I use the Hesco .470" lift cam in my 4.4L, MPI, H.O. head, engine and I like the performance of it. I also added the Cloyes double chain/roller cam, advanced 4 degrees. This lowers the rpm at which the engine makes maximum torque, which is just what I wanted. After spending alot of money and time, I would have been better off to just install a stock H.O. 4.0L engine a called it good. Go to my website for some 4.0L info.
http://homepage.mac.com/jefe/
regards, as always, jefe

I have to dissagree with that.
the 4.0L injectors are a big sore spot in the whole MPI set up. they are marginal for stock use, and any improvement on any other part of the system will make that painfully obvious. The Mustang 24lb/hr injectors are a cheap fix, and you can usually sell of the spare 2 injectors.

We haven't had any problems. We started with a 4.0 bored .030, with a 258 crank, longer rods and custom pistons (stock compression), and stage 2 mopar cam. Everything else is stock including the injectors. It dynoed at 230 H.P. and 320 LBs of torque, no pinging or miss.:) And it kicks ass on the trail.:smokin:

who'd you get the pistons from?

Sundowner wrote:
"the 4.0L injectors are a big sore spot in the whole MPI set up. they are marginal for stock use, and any improvement on any other part of the system will make that painfully obvious. The Mustang 24lb/hr injectors are a cheap fix, and you can usually sell of the spare 2 injectors."
Sundowner,
jefe here. Using larger Ford injectors does help, but what has your mileage sunk to? If it drops as far as other folks I know who have done this, you might as well have a V8. My point is the farther you get away from stock the more you're going to have to "pull on that string" to make it work. Anything you change has an effect on the other components ability to cope. Even with my idle miss/lean out problem, I get just terrific mpg, especially off road with my set up, and I have dynoed 212 HP and lots of low end torque. I was not interested in HP only low end torque, and that's what I got.
Scramblin',
The secret to the success with your 4.0L block buildup is "stock compression". Raising the C.R. is what does in many of the 4.0L buildups in terms of knock. I wish now I wouldn't have started with a 4.2L block and done it your way instead.
regards, as always, jefe

Originally posted by scramblin
We haven't had any problems. We started with a 4.0 bored .030, with a 258 crank, longer rods and custom pistons (stock compression), and stage 2 mopar cam. Everything else is stock including the injectors. It dynoed at 230 H.P. and 320 LBs of torque, no pinging or miss.:) And it kicks ass on the trail.:smokin:

Where did the torque end up? Does it still start around 1,000rpms and stay mostly steady from 1500-3000?

Gee, Jefe ...
My 4.2/+.060over/4.0/MPI/+4*dbl rollerHesco camed mill ripps and roars ... no pings ... just sings.
Rummp, rummp ... torquey little sucker too ...
Sorry fella :flipoff2:

... oh, and it'll rev past 5K on command ... and like it.
... and double oh, it idles at 600 like a kittn purr'in on yer lap.

That's the breaks.
Some do it ... some don't.
Your's misses ... mine won't.
:D

Where did the torque end up? Does it still start around 1,000rpms and stay mostly steady from 1500-3000?

Yes it starts at almost idle and goes to about 3300 RPM.

Scramblin