first stroker help help help

[brokejeep]

Hello,
I am debating wether or not to build a stroker. I currently have a 258 with a 4.0 head running the obdI injection. I recently developed a knock/noise and started looking for a potential builder block. I found a 1988 renix 4.0 that was recently rebuilt. It turns out the owner has more money than sense and built the motor for a cherokee crawler then after a few trail runs decided to rebuild the entire rig and start with a 5.7 vortec and go to dana 60's. The story he gave me is his father owns the local napa and his brother own a machine shop and they built the motor for him. The motor was bored .30 over and had all new parts installed. My question to the stroker guru's is this a good starting point for a stroker build??? I know nothing if the motor has been decked or what pistons were used. Is it possible to take this motor swap rebuilt 4.0HO head and swap in my 90 258 crank and rods??? What problems would develop and what other work would need to be done to make this a proper stroker that will be reliable??
thanks in advance
I was thinking of using the rock crawler recipe

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
Ford 24lb/hr injectors with stock 39psi FPR for '87-'95 engines, stock injectors with stock 49psi FPR for '96 and later engines
240hp @ 4700rpm, 315lbft @ 3000rpmteam ramrod

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[Cheromaniac]

Since you already have a fully assembled 4.0 HO head plus 258 crank/rods, what you really need is just the 4.0 block to use for a stroker build so it seems pointless for you to tear down a complete, rebuilt engine to use only the block as a donor. You're better off just buying a useable bare 4.0 block from a junkyard for your stroker build. It'll be a lot cheaper and you'll be adding a whole host of other new parts anyway (bearings, freeze plugs, pistons, oil pump, timing set, cam/lifter kit, upper/lower gasket sets) to complete the build.

[brokejeep]

Ok, I removed the head from the rebuilt 4.0 motor I bought to replace it with a HO head. The pistons travel to where they are level with the top of the block. If I replace the crank and rods with a 4.2 crank and rods will it push the piston past the top of the block??? I also found that the pistons are dished a little and appear to be similar to the silvolite uem-2229 pistons. when you use a 258 crank does it increase the up stroke or down stroke of the piston?
thanks again for the help

[4.whoa]

Yes, the4.2 crank adds stroke. But its up AND down - spinning. If you use 4.2 rods and 4.0 pistons it should be a little below deck- head gasket surface. The 4.2 rods are shorter, to compensate for the bigger stroke. If you used both the 4.0 rods and pistons it would pop them out the top, that's why you need aftermarket pistons with 4.0 rods.

[brokejeep]

thanks for the help.... so will I need to deck the block? or will I be fine with a little lower compression ratio??? Sorry for being a total newb I have owned several different jeep and tackled the 4.0 conversion a while back. now I am wanting the stroker. there is alot of information and can seem a bit over whelming. My over all concern is with quench and the compressin ratio.

[Cheromaniac]

Just go to both of the links in my sig. to get an idea of what's involved.

[BADASYJ]

All you need to do with your new block is change out rods and crank. You can take the 4.0 rods and pistons to a machine shop and they will press out the old pins and change the pistons over to the 4.2 rods for ya. Then you just have to assemble the motor with some new bearings and your done. I wouldn't worry about decking the block unless you want to tear the motor down to bare bones.
Get contact info for the guys that built this motor and get some more info on the build specs.