Cross reference 258

[Joe4310]

Want to pull top half of 258 and have it worked over. It's bored.. HEi
Doing a tub off of CJ 5. Motor rolls nice but slight tick and
No adjustment. While it's out what can I do to get all I can get out of this motor. Cherokee is under cover
Wisdom is money....

[joe]

I like the 258's for what they are. Reliable low end grunt motors but not long legged high RPM zoom zoom motors. Perfect for CJ's and adequate for FSJ normal use. Don't know what mods or money it'd take to turn a tractor motor into a fast motor? Some folks swear by swapping a 4.0 head onto a 258, but I have no experience there. The few 258's I've had all liked better breathing. My favorite mods are: A/ Send the Carter BBD carb to the trash bin. I prefer the Weber 32/36 but an MC2100 works well also. Along with that a better exhaust is a great help. I've ran the $$$ Clifford headers cause at the time that was all that was avail but likely there are others now. Mine were single output headers feeding a single exh pipe. Never felt the need to run duals on a 258. Since you already have swapped in an HEI ignition. That's a good mod and I'd keep it. The above won't make the 258 fast but IMHO more "responsive". Last one I did was in a CJ8 w/4.10 gears and it worked great on/off pavement. If ya just gotta have "faster" I would swap in a complete 4.0 Just one man's opinions. Ya might check on some CJ specific forums and see what those guys are doing with their 258's. Wonderful motors for their intended use.

[itselliot]

I did the 4.0 head on a 258...
really have to watch out for the water ports in the rear of the block they are mismatched and need plugging in the head.
A 2100 (1.41 Venturi) and the stock XJ exhaust header on the 4.0 head along with a cam upgrade (to what is generally called an RV towing cam) and I can smoke the wheels even when I have 2:73 gears....but went to 3:54 and .....I am more than pleased.......There are Stroker options, But I am not versed on that topic.

[Zorm]

I did what itselliot did and had the HEI from on old Chevy, not the crap of fleybay. Was a nice engine, after regearing to 3.51, was even better. Right now, changing the FI management system in my 4.6 stroker. but have never had it on the road yet.

[Joe4310]

Wanted to thank all for responses. Working from back to front on this thing so it will be a couple "months/years", prefer the former, before I get to the motor. Thought I would just dress her up but it seems alittle rediculous not to address the one thing that pushes us down the road when all other systems are being addressed. Buy a Cherokee and then dismantle my cj. Might have been drinking that day...