I have two 258ci motors in my barn. One is running and could be re-installed in a vehicle. They other is rough...might run, but somebody took the timing cover off to change out a chain and left it off then laid the motor aside on a dirt floor in a barn. It is going to be my organ donor.

I have a noisey 4.0 HO in my '94. It runs excellent...just makes coffee can full of rocks noise. I am considering a winter re-build and have an excellent machine shop in my town.

I have heard that if I pull the motor and do an ordinary refurbishment rebuild but use the crank and rod set from a 258 that I will have an instant STROKER MOTOR. Kinda like "Instant Breakfast" - that powder you dump in a glass with milk and it's supposed to be the same as food.

My question is: Is this true? Can it be this easy?

I've spent a lot of time searching through the archives and there are a great many threads but I haven't found one that collects the true skinny in one place.

 

I have heard something like this.......not sure if it's possible, but I heard something about swapping the head also.

 

x2 it is also ringing a bell to me too and fyi the instant breakfast is just as good...i have one every morning including as I type lol

 

Check out jeepstrokers.com and read up. That is the most basic stroker combo but your compression has to be checked and a few other parts added if you want the full potential.

Like a cam to handle the increase volume, ford injectors, adjustable map, intake, header and bored TB. You have the best head for the job and a simple port and polish would help alot.

the list goes on

 

258 4.2L engine

3.75 in (95 mm) bore
3.895 in (98.9 mm) stroke



242 4.0L engine

3.895 in (98.9 mm) bore
3.414 in (86.7 mm) stroke



The only thing I would wonder is if you could still use the 4.0 block with that crank... Or would the pistons hit the head

 

You can use off the self pistons with the 4.2 connecting rods (which are shorter than 4.0) but you have to get custom pistons if you want to use the 4.0 rods which = $$$

I've looked at every setup possible. I think the best would be bore .30 over, 4.2 crank and rods, 30 over 4.0 pistons and a comp cam. If the money is there, upgrade the valve train to it doesnt blow up on you.

FYI, LS1 valves will work in our heads and are bigger, they also add a few cc's to the combustion chamber.

 

The LS1 valve will work as will most SBC valves but from what ive seen the issue of valve shrouding kinda of cancels the benifits out but can be made to work with lots of machining to the CC on the jeepstrokers site use the comp ratio calculator play with the numbers IMO a good port/polish will give you more benfits than the valve swap. The 4.5 simple stroke aka "instant breakfast" idea is very doable but I would go with the 4.6 since you have a good machine shop nearby the only issue with this is if you go to a COMP CAM you can not use the valve springs that they sell you will have to use something like mopar performance springs but its not that big of an issue just a heads up though. My $.02

 

Gentlemen ............

JEEP MOPAR 4.7L IN-LINE SIX STOKER MOTOR FOR 91 TO 06 MODELS PN P515520X
JEEP MOPAR 4.7L IN-LINE SIX STOKER MOTOR FOR 91 TO 06 MODELS PN P515520XID:P515520X
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Description
JEEP MOPAR 4.7L IN-LINE SIX STOKER MOTOR FOR 91 TO 06 MODELS PN P515520X
Retail Price: $4,000.99
Online Price: $3,509.48
JEEP MOPAR 4.7L IN-LINE SIX STOKER MOTOR FOR 91 TO 06 MODELS PN P515520X
JEEP MOPAR 4.7L IN-LINE SIX STOKER MOTOR FOR 91 TO 06 MODELS PN P515520XID:P515520X
JEEP MOPAR 4.7L IN-LINE SIX STOKER MOTOR FOR 91 TO 06 MODELS PN P515520X
Retail Price: $4,000.99
Online Price: $3,509.48 http://www.moparsupercenter.com/jeep...xp515520x.html


Thats all I have to Say bout them . . . .

 

^ but that takes the fun out of building one yourself.

 

It also takes the worry out too.

 

Great if you have deep pockets...

 

Yes you are right 258 crank and rods with 30 over pistons will give you a 4.6L motor.

 

the radiator fan on my 87 wagoneer isn't coming on as it should; any procedures on how to carry out a diagnostic.

 

Don't forget this one by Golen: I've heard it's one of the best and I'm saving for it.

http://www.golenengineservice.com/html/jeep.html

 

idk Ive heard of a few bought stroker motors failing pretty quick like the titan engines, I would be pissed if i spent 5000 on a motor and it die in 20K miles