flip flop.... long winded thread

been on again/off again alot lately on V8 swap.... taking the pro-jection off, you name it, i have not been happy with the way the jeep has been running.

the set up i have been thinking about if i go the V8 route is a ford small block w/ford t18 (granny geared) tranny and buy the D300 adapter so i could gear the tcase to 4:1

after hours and hours of work, i got the pro-jection working great (i know this thing inside and out now R) )

an alternate plan of action is the 4.0 head swap. my 258 has just rolled over 12k mi on its rebuild. it has a slightly bigger than stock cam, DUI ignition, borla header/exhaust and is pretty peppy for what it is but you know how it goes.... "just a little more power" :twisted:

the delima is... i had a rebuilt 289 given to me the other day. it has 10k mi on the build and new water pump, oil pump, distributor, plugs/wires, fuel pump...tons of other stuff new in the box. i can be near 300HP for a few hundred bucks... get a junkyard ford T18 and start saving for the D300 adapter $500 and the tera low 4:1 kit.... $500 or more. that'd put me at about a 120:1 crawl ratio or keep what i have, do the 4.0 swap and regear my D20 tcase and be at a 97:1 crawl ratio.... who knows, maybe i will find a texas bolt pattern D300 :?

how hard is the 4.0 head swap??? i have read that the water jackets will need to be plugged depending on your 4.0 donor... the exhaust manifold/header will come from the 4.0 but i will be able to use my intake/projection off of the .258

i have searched this topic alot and would like to get some opinions from a few of you "pros" ....lynn, nickmill, sparky, ect. R)

penny for your thoughts

 

why do you want more power so badly? i am not trying to be a smartass but what is wrong with what you already have? gas is expensive, do you really want to use more?

 

I know it is personal preference, but I vote on the V-8. Your mileage might even go up! Will the pro-jection go onto the V-8? Looks like your drivetrain is heavy duty enough to handle the extra power.
I love my V-8, these are supposed to be fun vehicles. I have owned three different toyota 4x4 trucks with 4cyl. and v6's and ridden in many friends jeeps with the V6 or I6, they all got the job done but were not as fun as the jeep with the V-8. The V-8 seems to be more versatile, better street performance, able to run sand and mud much better, haul or tow heavier loads, and of course, sound cool.
Down side, if driven hard, more stuff breaks, expensive stuff! Good Luck with your decision.

 

no matter what you do to an inline 6, it's still an inline 6
looks like the rest of your drivetrain can handle the V8
I vote V8
I'm not an expert though....
can of worms

 

thanks for the input guys.... the power is not the biggest factor to me, i'd stick to the I-6 in a heartbeat if i could find a bolt on D300. though i'd like the V8, the ability to run a T18 and a D300 is what i want.

 

go with more power. and I think in the long run that you will get better or the same gas milage with the v8. it is trying to pull a lighter vehicle. so if you take it easy on that go pedal it will be easier on gas.

 

so have you considered the np435 d300 combo it bolts up to the 258 6 by drilling and tapping one hole in the bellhousing and changing your clutch disc to ford spline,
I think the np435 is a great tranny

 

One option, in addition to the Scout D300 - if you can find one - the J-20 from 1980 on offered a WR T-18 with the NP208. That's a NP pattern which will bolt up to the D300. I'm not sure about the clocking or the spline count, but I believe that you can a clocking ring or a spud shaft to correct those if needed.

The 289 is only a 31 cid difference from the 258, that's a 12% increase. Hardly seems worthwhile, especially considering how short the 289 stroke is. Would be exciting in a Falcon or early Mustang, but not much grunt in a Jeep.

Not hard, AFAIK. Have you read Tim Weaver's article about this? I think it's gone now, but I have saved the text (no pictures). There are a few ways to plug the water passages - weld, JB-Weld, freeze plugs. You're right - you can keep the intake and use the 4.0L exhaust manifold.

 

That is a good idea too. The np435 and t18 aren't a lot different gearing wise. The t18 is smaller, which would, no doubt, make it easier. I really like my t18. I have a truck with the np435 and like it but that isn't a JEEP so it may be different. I also vote for the V8. You have the drivetrain to back it up, go for it. Just my .02

 

I'm installing a 360 AMC (plus power steering, Offy intake, HEI, fender well headers, 750 Holley - a little too big but it was free) in my '73 CJ5 in place of the 232 I6. Fortunately my old jeep came with the T18. Don't know about the 258 but the 232 was weak (didn't do bad in lower gears but ran completely out of steam on the highway), even though it ran good. I should have it complete within a few weeks. You're welcome to come take it for a test drive when I'm through and see what you think. Corpus isn't that far from Houston/Baytown.

 

thanks for the feedback guys, you've given me some great options to consider.

lynn funny you mentioned that site, i know george and live about 45mins from his place. great guy to do buisness with. go see him with alot of time to sit around and shoot the breeze.

i have looked into the NP435 and am still reading up on it. i'm also reading up on the SM465/D300. like i have said before, if i can add a little more HP to my .258 and put together a HD low geared tranny w/D300 tcase thats the route i will likely take.

i know for most wheelers anything around the 70:1 range is a good crawl ratio but i am finding myself getting into wheeling that wants a 100:1 or lower. if we had room in the CJ5's for a dual case set up i'd do it.

we are trying to make plans to come home this summer (and i wanna tow the Jeep) i am dying to get back out on Padre Island with the top off.... i've only been home once since Nov 2001.

here is a link to one of the better write ups i have found...


http://www.geocities.com/035jeep/40L.html

 

if i do the 4.0 head swap does anyone see any issues with me using my current ignition (D.U.I.) and using the holley projection thats currently on the .258???

 

I'll throw out another vote for the V8 as I'm also looking to do the small block Ford/T-18 combo. I have a proven 302 and tranny in my rock rig that'll be transplanted. I just can't imagine the 100 hp or so from my 232 comparing in any way to the 275+ in my 302.

I'm curious, and uninformed. Why go to the 300 instead of using the D20?

 

Crawl ratio. The D20 has a 2:1 low range, and can be regeared (for a reasonable amount) to 2.42:1 IIRC. The D300 is already 2.62:1 and can be regeared to 4:1.

 

correct... the D300 can go 4:1 and the best you can get the D20 is 3.15:1

 

Well I tell you what, The Jeep below was mine until about 4 years ago. I most enjoyed it when it had the 289 V8, NP435, and D300 with 35" tires and 4.88's in the pigs.

There was NOTHING better than cruising in that thing with just a bikini top on a nice spring day. That small block Ford sounded gorgeous at 3200 rpm.


I ran the AA adapter for the D300. I also redrilled the holes to clock the t-case up a little.

 

It all depends on what you want. There's no denying the sixes perform very well and in many cases have power approaching a V8. But if you've ever ridden a Harley and experienced that irresistable grin when you sit on it and fire it up...you'll appreciate the same feel of a V8. The V8's not only sound, and feel cool...they look cool. Even the lowly AMC V8's can be made to look nice.
Got a few more weeks to go on mine before it's ready. New cam, lifters, HEI, wires, water pump, oil pump, and clutch yet to install. AMC 360.

 

Sell the 289 and the 4.2 and buy a remanyed or rebuilt 360/401. To me, this would be the best option, especially since this is what I'm planning right now. Dave, your 360 looks good. Is that ford blue paint on it??? Like said before, a 258 is always going to be a 258. I have heard that the 4.0 head swap makes a good difference and would probably make a lot of difference with your cam. It's still not going to have the power of a V8 though.

Go V8

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