What power difference between the two?

I have the 99+ intake

Is this something the machine shop adds?

 

The power difference is noticeable, especially doing a before and after on the same day. The machine shop can install them at time of build or anytime later.
The problem with the cams especially anything over .450 valve lift is they will require different valve springs to prevent coil bind and these are usually heavier strength and the extra pressure on the cam will wipe out a lobe.

 

longer rockers just create more valve lift with stock cam profile. not a bad idea, but I wouldn't think your stock springs would like it very much

if you were to do camshaft, the second sounds better to me too

 

This seems to be the came 9 out 10 guys are using per my research at least.

http://www.summitracing.com/parts/crn-753901
Crane cam # 753901 - $146

Cam Style:Hydraulic flat tappet


Basic Operating RPM Range:1,500-4,500


Intake Duration at 050 inch Lift:204


Exhaust Duration at 050 inch Lift:216


Duration at 050 inch Lift:204 int./216 exh.

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Per Crane's site



H-260-2

 

If the factory cam lift is .405, as stated in another post in this thread, then adding a roller rocker ratio of 1.7 will raise the lift of the valve above .450. I'm pretty sure the factory rockers are 1.6, so taking the rocker to 1.7 would take the valve lift to about .478. If the factory rockers are 1.5 then valve lift with 1.7 rockers would be about .460. All of this is important because when building a head and measuring for coil bind a minimum of .025. That is an absolute minimum. If the Jeep factory followed the same protocol, then coil bind would happen when roller rockers with a ratio of 1.7 were added to factory heads. And coil bind is a recipe for dropping a valve and grenadine an engine. In addition, the cam that was suggested to Crawler comes with new springs.

Crawler is also installing o/s valves, and has a newer intake. He has also talked about porting the head. So absolutely a new cam would be noticed and would be worth his time and energy in my opinion.

Also, hydraulic flat tappet cams require a minimum of 110# on the seat. A high performance flat tappet cam will run #130-140 on the seat, based on the lift and design of the engine. An increased seat pressure of 30 pounds will not wipe out a cam. Improperly lubricated cam during installation, using old lifters, bad VT geometry could also be a culprit.

Cobra I think your wrong man. I like roller rocker as much as the next guy, but there is more to be done than just swapping out rockers. I would not be opposed to a roller rocker with a factory ratio at all. I'm all ears if you can back up you statements. But I think you are misinformed.

 

have you been able to find any dyno results to see if this is really gonna knock youre socks off

 

Dyno? Not yet. But, manufactures, and others have said 40-50hp. With head and cam. I am sure someone can post if this is achieveable by what I have and will have.

If this is the case, I would be happy.

Re-cap.

Head machined is $170-$450 (machine shop will call me back)
Labor $200 (local guy that has done stuff for me before).
Cam $160
--
$660 (medium price range) for 40-50hp?

 

You can get valve springs that will allow greater lift with out additional seat pressure. I have built countless heads with different VS all running close to the same seat pressure. Spring rate is an amazing thing. Do some more homework man.

 

The Crane cam that you posted on this page is also a good choice. Compared to the 505 cam the Crane is a dual pattern with less intake and more exhaust lift with a lower LSA. About all of those things will increase torque for the sacrifice of HP. Torque is what you drive, HP is what you race.

 

Go ahead and build what you want, I am just telling you what will work and what doesn't. Flame on if you like but in the end I won't say I told you so.
.405 lift is with the stock 1.6 rockers. Stay in school and do the math.
.253" cam lift with 1.6 rockers is .405 valve lift. with 1.7 rockers is .430" valve lift.
How many guy have a 'larger' cam and have 150,000 mile reliability like a stock cam?
No matter what cam you have, you are still stuck with the poor flowingintake manifold and worse flowing head. Don't get your hopes up in a 'ported' stock head. This has all been done before. Either you learn from the past, or you make the same mistakes all over again.

 

I will admit that my math was incorrect. I was quickly trying to back into the information based on valve lift and not actual cam lift. However, I stand firm on the theory's stated.

Hopefully Crawler has realistic expectations of what will be accomplished by replacing the cam and modifying the head. The 4.0 is what it is. It will never be a high revving, high HP, 140 MPH in the 1/8 mile kinda engine. But if it were me, for the money, a cam and head modification are money well spent. With out a doubt Crawler will make more power than a factory 4.0.

Good chattin with you Marty. You and I are finished here.

 

Typical, just what I expected.

 

I was trying to be polite by dismissing you.

 

Now that's an oxymoron.

 

although i certainly am no expert im gonna go out on a limb and say its doubtfull youll see 40 to 50 hp with those mods but hope im wrong