CA smog legal 4.5

[rockslut]

I am looking at stroking my 4.0 in my 95 XJ. Already have cat back exhaust, 2000+ intake with throttle body spacer and a conical air filter. My current engine has less than 90k on it. The 7120 head was recently shaved, valve job. New oil pump and timing chain installed (all with less than 3k miles on it. The engine runs strong but I need more HP to push around my one ton axles and all my camping gear. With my limited reading on here this is my plan. Feel free to shoot holes in my plan so I get it right the first time.

I will have a late model YJ 4.2 crank and will get the earlier 4.2 rods if they are much stronger. Have them machined, balanced, new ARP bolts and polish the beams if thats worth it too.

Would like to put my 4.0 pistons on those rods and run it without boring the cylinders. My question comes in with quench and compression. Where will that put me since my cylinder head has been machined once and the block is stock? I don't mind running 91 octane but it would be nice to keep it on 87.

After that, the camshaft ordeal. Not sure if there is a cam that will live and still allow me to smog in CA? What about just going with roller rockers and keeping the stock cam? Is an aftermarket worth it on a street driven rig?

Any help is appreciated.

[Flash]

I am looking at stroking my 4.0 in my 95 XJ. Already have cat back exhaust, 2000+ intake with throttle body spacer and a conical air filter. My current engine has less than 90k on it. The 7120 head was recently shaved, valve job. New oil pump and timing chain installed (all with less than 3k miles on it. The engine runs strong but I need more HP to push around my one ton axles and all my camping gear. With my limited reading on here this is my plan. Feel free to shoot holes in my plan so I get it right the first time.

I'm not the one to be talking to you about IM.......as i don't have to do IM or safety inspection either.......... BUT here go'sIf you raise the compression, it could raise the nox IM.....which you will be doing with a simple stroker(throw a 258 crank and rod into a stock 4.0) any where you can improve Quench Height you will improve Nox IM as well as performance.
What is quench??? Read up here viewtopic.php?f=27&t=73

I will have a late model YJ 4.2 crank and will get the earlier 4.2 rods if they are much stronger. Have them machined, balanced, new ARP bolts and polish the beams if thats worth it too.

[b]I don't thing rod strength is and issue inless you were planning on making a lot more power, aka would not pass Cal IM eng[/b]

Would like to put my 4.0 pistons on those rods and run it without boring the cylinders. My question comes in with quench and compression. Where will that put me since my cylinder head has been machined once and the block is stock? I don't mind running 91 octane but it would be nice to keep it on 87.

With 90,000 miles on the motor, you will need new piston and more then likely a bore job as well(you machine shop would be the best one to answer that one)

After that, the camshaft ordeal. Not sure if there is a cam that will live and still allow me to smog in CA? What about just going with roller rockers and keeping the stock cam? Is an aftermarket worth it on a street driven rig?

http://www.jeepstrokers.com/forum/viewforum.php?f=27
I do like the idea of the roller rocker......with maybe a 1.7 rocker ration w/stock cam

Any help is appreciated.

[rockslut]

Well, if I am going to have the cylinders cleaned up then I might as well get the right pistons and be done. Looks like a 4.6 is going to be the way to go.

[Cheromaniac]

Would like to put my 4.0 pistons on those rods and run it without boring the cylinders. My question comes in with quench and compression. Where will that put me since my cylinder head has been machined once and the block is stock? I don't mind running 91 octane but it would be nice to keep it on 87.
After that, the camshaft ordeal. Not sure if there is a cam that will live and still allow me to smog in CA? What about just going with roller rockers and keeping the stock cam? Is an aftermarket worth it on a street driven rig?

If you kept the standard bore size and reused the original pistons for a 4.5 stroker, the CR would come in at about 9.8:1 which will require premium fuel.
I suggest you go for a +0.020" overbore and use Sterling 677CP pistons on 4.2 rods. Despite the head shave, the CR will be a more manageable 9.4:1 and you could run 91 octane with the stock cam. You'll essentially have a slightly modified "poor man's" simple stroker similar to mine.