I am getting ready to rebuild a 84 258 engine for my jeep. i am writing to look for help on what parts i should use and also how to make it a little more powerful, i have the engine out. i am going to put a weber carb on it and dual exhaust, but any other suggestions would be great. Thanks, Pat
I have considered doing the 4 bbl swap on my 87 258 as well. All emissions are stripped and I need more power. I was looking into a Clifford performance 4 bbl intake and holley 390 cfm, plus a header and cam. What is the power increase and gas milage like with the 4 bbl? Also, what about the coolant lines that run into the intake, and the vaccum actuator for the heater console?
You ask a real interesting question. Wanting a little more power can be an addiction and lead to wanting more and more. Rather than spend thousands of dollars, just drop a V8 in it. The cost will probably be less that what it would cost you to build up your system. For example:
Competition Cam - $140
Springs, Retainers, etc - $150
4.0 head for replacement - $100.00
used value cover-$40.00
Significant head work and values - $500.00 (stainless steel values, 2.02 & 1.75, harded seats and retainers, brass guides, .060 off the head, polished and ported/matched to exhaust.
New Rods, Pistons, Rings - $225.00 for forged pistons add $125.00
Boring of the engine - $50-75
Weber Carb - $350, Holley carb - $250, New intake manifold - $150-175
Jacobs Electronics - $200-$300
Headers - $200.00
Mechanic charge,unless you do it. $750.00
That is -- unless you just want to see what a I6 will do or you know precisely what you want to do with the jeep and then can adjust it to fit what you want. Peace.
I rebuilt my 258 a year ago, it ran great.......then the block cracked with about 1000 miles on it.......fought with the rebuilder to fix or replace (no luck)
Do yourself a favor and put a 304/360 in it.....I bought a donor Wagoneer for a grand, pulled the engine and slapped in my CJ.....runs great and I have gobs more power!! I6's have there pros/cons but you cant beat the extra cubic inches.....my $.02
Go to my Jeep site and read Tim Weaver's articles and take a look a some of the things I did to mine.
Both Clifford Performance and
HESCO are good sources for upgraded components.
I like Badger brand pistons (from NAPA)
A heavy duty (not hi-volume) oil pump is a good idea.
Tell the cam shaft vendor what you will be using your Jeep mostly for, etc.
A 1991 4.0 head (see Tim's article) and Webber/HEI or an MPI will top it off nicely.
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