Did the Intake manifold swap

phaythe said:
bump!

Still hoping Dino might be able to shed some light on my question about the 753941 camshaft? ..

I think that cam would be way too big for a 4.0 given that you're limited to a maximum of 5250rpm. It'll also be a dog at low rpm given that the stock CR is only 8.8:1. The 753941 would do much better in a high compression stroker (10.0-10.5:1).
I suggest you go for the 753905 cam and increase the CR to 9.5:1 by using the Mopar Performance 4529242 head gasket, mill 0.010" from the head, and mill 0.020" from the block. Use the aforementioned springs/retainers/locks and add 0.030" shims (Crane shim kit 99179-1) under the rocker arm bridges to correct the lifter preload.
Port the head using my write-up as a guide and you'll be just about done with the internals.
 
My interest lies with the more extreme cam since future upgrades include stroking to 4.7L, a T04 turbo and a switch to propane for fuel. I'm going to replace the ECU with MegaSquirt, and set my rev limit at 6k. So I'm definitely wanting a cam that can give me a wide powerband up top. This engine won't be for wheeling at all. So low end power, I don't care about. It'll be for rallyx and drag, and won't see anything below 2500k when I'm done, pure race engine. So I guess essentially, will the 941 just totally be a disappointment before boosting it and I should just wait to snag the cam when I build the stroker? I figure, if it'll give me even marginal gains now, it'd be fun to have, as it's something I can realistically afford to do while I'm working on the buildup of my other vehicle.

And where can I learn the info I need to say, determine that I do indeed need shims to correct lifter preload. Only thing I can ever seem to find is how to calculate compression... :P Any good resources online? Books I should check into?
 
phaythe said:
And where can I learn the info I need to say, determine that I do indeed need shims to correct lifter preload. Only thing I can ever seem to find is how to calculate compression... :P Any good resources online? Books I should check into?

My page http://www.jeep4.0performance.4mg.com/valvetrain.html has some info. on how to check lifter preload and how to correct it.
Since you're building a pure race engine, you could consider one of Crane's solid lifter cams and install adjustable roller rockers.
The camshaft has a harmonic that could break a timing chain as you approach 6000rpm because it's supported by only four bearings, so I suggest you replace the stock timing set with a gear drive if you're gonna be spinning over 6000rpm. .
 
Back
Top