Slim357

Iv been researching what people have done when they built their engines but not really sure what would be best for what I want. Iv heard people say to put ls1 valves and springs in the 4.0 but not sure how much this would help or why you would put chevy parts in a Jeep. The main thing I am looking for is more useable torque in the power band and to bring the power band down to about 1500 rpms to 2500 rpms. Any suggestions?

Donnie_K

If you've already done a header, 99 intake, and all that good stuff, then just freshen up the engine with new rings and bearings, and have the head ported and polished, and cut for the ls1 valves and springs. Bigger valves = more flow. But flowing more at the valves doesn't do you alot of good of the ports, intake, and exhaust aren't opened up.

Slim357

makes sense just worried that doing the ls1 valves and springs would mess up the comp cam im getting. I plan on doing the 99 intake wen i swap my motor over to the HO engine but I gotta figure out how to make the renix throttle body to work on the HO intake. I dont wanna pay hesco 500 for their kit to use the renix sensors on the HO throttle body.

Donnie_K

https://www.cherokeeforum.com/f51/re...ts-easy-47578/ Just swap the head and manifolds, not the whole motor, lol.

Slim357

hmmm thats interesting never seen it done like that b4 guess id just need to heat skrink the wires I would have to splice together right?

Slim357

Just realized hes got the manual trans Iv got the auto so there are more wires on my tps

Slim357

probly a stupid question but..... would putting ls2 valves increase my compression ratio any. I think I am going to swap in a 93 motor and do a 4.6 stroker with 8.75:1 cr. Mainly so I can still run cheap gas thru it lol. Here is the specs for the engine. Let me know what your thoughts are.
4.6L Low-buck, low CR "rockcrawler"

Jeep 4.2L 3.895" stroke crank
Jeep 4.2L 5.875" rods
Silvolite UEM-2229 +0.030" bore pistons
Increase piston dish volume to 30cc
8.75:1 CR
CompCams 68-115-4 192/200 degree camshaft
Ported HO 1.91"/1.50" cylinder head
Mill block deck 0.035"
Mopar/Victor 0.043" head gasket
0.058" quench height
240hp @ 4700rpm, 315lbft @ 3000rpm

grainofsalt

From what I have read, the LS1 valves really aren't worth the money to put them in. There are some LS1 valves that have a dish to them, which adds some cc's to the combustion chamber. Which helps lower the compression. You could also recess the valves to get more volume in the combustion chamber.

I decided to do the Modified "poor man's" stroker, For the long rod advantage, And also kept the stock camshaft, Many aftermarket cams die after about 30k due in part to smaller lobes I hear.

I'd suggest you head over to jeepstrokers.com for the stroker questions.

Slim357

kool thanks for the link. Iv never heard any one having issues with aftermarket cams. Was thinking of doing the extreme 4x4 cam from comp cams. Guess I better do my research before I put a cam in it.

Donnie_K

I'm running an extreme 4x4 cam by comp. Have been for over a year now. I'm not stroked though.

Slim357

hmm wonder is it makes a difference in the longevity of the cam