First Stroker, Please Help

[diamondjim05]

I have a 97 Grand Cherokee with 212,XXX miles and its time for an internal freshen up. I have been considering a stroker for a while now, and i have some questions. First, if i replace my crank and rods from ones out of a 258 and then bore my block out .030, then i roughly have a 4.7 right? When i order my oversized pistons, do i need to order them for the block or for the connecting rods, or does it matter? As for the wrist pins, can I use the stock pins with the 258 connecting rods? Im ordering an aftermarket cam from comp so no worries there. Also, what crank would be best to use that would be most readily availible or common at a junkyard and require the least amount of machine work or prep work (Ive heard that the nose for the harmonic balancer is longer on some of the 258 cranks). Thanks for all the help in advance.

[Cheromaniac]

I think you'll find most of your existing questions and any future questions you'll have answered on my stroker build-up site.
A set of +0.030" pistons in a stroker will put displacement at 4587cc or 4.6L. If you buy new pistons such as the H802CP or H825CP, they'll come with new piston pins and your machine shop can press them onto the rods. The small end of the 258 rod is the same size as that of the 4.0 rod so the pistons will fit. After you've bought the pistons and taken them to the machine shop, they'll measure them and bore/hone the cylinders as required.
Any used 258 crank you buy will likely need some machining (resizing of rod/main journals). Cranks made from '87-'90 will have the shorter 54mm snout and not require a 1cm thick spacer to be placed in front of the harmonic balancer but they're the hardest to find.

[amcinstaller]

i think the 12 cwt cranks (with the longer nose) were mostly found in amc's, not too common in jeeps. or am i way off on that one?

[seanyb505]

I believe the 4wts were only offered for a few years, 87-90 in the YJ. Everything else is a 12wt. For peace of mind, SCAT is offering a new crank, not a reman. They want 400 but they can be found for less elsewhere.

Edit: Im dumb, I got it mixed up for when I was looking for my crank - 87-90 are the only 4wt crank that dont need the snout cut or need a spacer.

[IH 392]

The application doesn't matter for the crank, the year model is what determines what crank you have, the 12wt cranks are 1970 to 1983 (I'm not 100% positive on it being that late??) then they went to the 4wt cranks, the type of belt determines the snout length, the V belts are the long ones and serpentine belts are the short snouts.

[amcinstaller]

iirc in amc cars the 12 cwt stopped in 81. again, i could be wrong. there were other changes to the 4,2 in that year, like that stupid plastic valve cover

[cigarluvr]

Thats odd...I have a 4wt crank with a longer nose? What do I have...hmph...

[IH 392]

iirc in amc cars the 12 cwt stopped in 81. again, i could be wrong. there were other changes to the 4,2 in that year, like that stupid plastic valve cover

I thought it was about 1980, so '81 is doable, the book I looked in is FUULLL!!!!!! of discrepancies!

Thats odd...I have a 4wt crank with a longer nose? What do I have...hmph...

That would be the "intermediate" crank, they went to the 4wt but still had "V" belt accessory's.

[amcinstaller]

yea, i meant 80 was the last year of 12 cwt. 81 brought the stupid valve cover, and i think the 4 cwt, perhaps the long snout v belt one.

[Cheromaniac]

Thats odd...I have a 4wt crank with a longer nose? What do I have...hmph...

Then it's an '81-'86 crank. You'll find all the info. at http://www.angelfire.com/my/fan/selection.html

[diamondjim05]

Thanks for all the help and for the links, i think i have all the info i need. Thanks again!!!