350 swap?

[CW]

hey,
Im going to swap engines later this summer because my jeep has 245,000 on it and is getting tired. I would really like to drop a 350 sb in. Is this even possible? My other options are a 307, a ford 289, or a stroker. What would be the best in the xj, I would really like to go to a V8. How much power and torque can I really expect from a 4.7 stroker compared to a built 350? Can I use the jeep tranny or am I going to have to find something else? Any advice would be a big help. -thanks

[CheapXJ]

if you want something reliable, you pretty much have to swap out the tranny. the manual could be a ba 10/5 which is barely strong enough for the 4.0L, an ax15 (good tranny, but I doubt it would hold up to a v8 very well) or the aw4 auto (would probably hold up, but the electronics make this almost impossible to retain)

another thing to think about, for a little more than the price of an adapter (maybe even less), you can have a better tranny anyway ;)

[eric91xj]

My opinion is no a 4.7 stroker probrably can't keep up with a decently built 350, but the other thing to consider is you can't use the power from the 350 anyway because the XJ's body/frame is'nt strong enough, your gonna twist the poor thing up. If you want that kinda of power your gonna need some serious support added to the underneither of it. You will need to find a new trans to use with your 350 and possibly axles too, don't know how a Dana 35 is gonna hold up to possibly over 300 hp from a 350 along with possible bigger tires.

eric

[Beezil]

you can't use the power from the 350 anyway because the XJ's body/frame is'nt strong enough, your gonna twist the poor thing up

if yer gonna make a statement like that, it'd be good to back it up with testimony from first-hand experience. posting what you *think* might happen is not helpful.

There are plenty of v-8 converted XJ's out there.

[4ward]

I heard that you can't put a D60 under an XJ without massive bracing too:rolleyes:

C.W. Are these motors that you have laying around or are these just the choices you've come up with? I'm a big fan of the 302 swap personally. It's lighter than a SBC and it's a very healthy motor even in stock form. I have 90% of an LT1 sitting in my barn that I've collected all the parts for free, so that's the route I'll be going for my XJ, but my rock buggy will either get a 302 w/ aluminum heads or a 4.3.

Sean

[Beezil]

One bung,

when i asked you the question "if you could put ANY engine ina jeep (tube buggy was mentioned) what would it be?"

didn't you say caddy? I know you have the lt-1 sitting there, i figure that is the reason you are not using the powerplant you suggested when we were discussing it....

i thought you said something about the amount of hp and torque it produced, and how LIGHT is was compared to the 4.0.....

more please.

this is a thread hijack.

[4ward]

Yep, I was wanting Caddy shortstar, but they aren't as easy to come by as I suspected. And the inherent wiring nightmare that ensues has got me leaning in other directions.

My brother told me last night that an LT1 only weighs 80 lbs. less than an LS1. This started me thinking on just going with an LT1, but a 302 is still lighter and produces enough horses. So, I'll probably end up dumping the LT1 into the heep and a 302 into the buggy, but I may still go 4.3. Is that wish washy enough for you?

Also, a TH350 weighs less than a C4 according to my hot rod buddy. so the chevy drivetrain is working its way back into my head. I need to find definate weight #'s on trannies and not just heresay.

Sean

[Beezil]

and that th350 doesn't require peripheral input does it?

I'm not going to start mine until you've guinnea-pigged yours.

"you go first".

[5-90]

The SBChevvy conversion in the XJ seems fairly common - you can even get a kit for XJ/MJ from Advance Adapters. The Unibody is really rather rigid - unless you get nuts (blown & laughing) I see no reason why the frame couldn't hold up to a well-build SBC - and don't we have a 454XJ running around here somewhere?

I've considered the mod myself in my 87 Project XJ, but I just happen to prefer the I6. The torque peak is lower in the I6 than in the V8, and that translates to more "usable" power at low speeds. Going to a V8 would require, in my mind, some heavy regearing. I'd also consider going to a D44 fore and aft so you don't grenade the D30/35 (IIRC, they are pretty borderline for V8 applications.)

The THM350/400 are hydraulically and vacuum controlled (remember transmission modulators?) so swapping to them is a non-issue. Even the AW4 is pretty self-contained, as the early versions keep pretty much to their own electronics (the Renix TPS was a "Split" unit - two in one. Half was for the TCU, the other half for the ECM.)

Manuals - An AX15 is a minimum, but I'd be happier with at least an NV3550 behind it (I'm a firm believer in overkill.) If you have 87-90 with manual, you have the BA10/5, which just isn't up to scratch. Even behind the stock 4.0, it's often scrapped - damn thing usually costs more to rebuild than to replace.

I still keep the idea of a (blown?) 383 Stroker SBC on the back burner - it's one of my favourite SBC buildups. Good effiency and power compromise, and easier to pass thru the Smog Nazis here in California. Even without emissions controls, it's still a damn find engine. The 289 is a possible, but may be more fab work than you want to get into - it's up to you. Either way, the unibody should be able to take the torque, but the AA kit looks like it provides some reinforcement, and with the work you are going to get into either way, I'd think about some bracing for the 289.

I'm going to assume ID doesn't have a smog programme (it's a good concept, but very poorly executed here in CA,) so that's probably not an issue. For Californians, the stroker is easier, as you retain the OEMR appearance.

Going to the SBC could allow you to build an engine on oldtech, and get the Edelbrock or Holley PFI kit and gain some tuneability. Both kits are designed for retrofit applications, and should be pretty easy to apply and tune. Think about that at all?

Anyhow, I hope this provides some food for thought. I'd definitely think about upgrading most of the gear train for the SBC, tho. The NP231 tcase is pretty rugged (specs at www.newventuregear.com - as well as their transmissions.)

5-90

[dave]

i own an xj with an LT1 and 4L60 in it.. no twisting yet and i beat the hell out of it.. if its an 87 the only clearance issue you will have is the headers.. they fit but its tight.. also a couple pulleys need to be machined and if you want to run AC in it you need to fab your own mount . the 4l60 is awesome.... keep in mind .. a harness ( 800) and reprogramming the computer ( 200) as costs.. i couldnt fit the optima in the engine bay so its in the rear.. you can fit a reactor battery under the hood but they are pricey ( 400 ) all i can say is it is awesome and nothing compares.. if you do it do yourself a favor if you drive it on the street.. run 4.10s.. my 4.56s are too tall for the 35s i run with that torque. going into overdrive with heavy throttle it misfires a bit because there is not enough load on the engine.... just do it.. LT1s are cool.. and a bit of advice use GM o2 sensors the aftermarket ones made my engine misfire etc.. they blow! and its kind of cool to drive to a GM dealership to have them pull codes off your LT1 thats in a jeep :D they all make funny faces at you .. hehe


the frame twisting thing.. i dont think so .. i will be adding a cage in the next week to make sure.. but its been wheeled hard and tailgate still opens and closes effortless as do the doors. ::shrug::

[5-90]

Just to make sure, but isn't the 4L60 a computer-controlled THM700R4? Just wondering...

5-90

[THE_OWL]

There are a few other considerations:
you need a good amount of lift because the oil pan gets intimate with the front diff and the oil filter.

ImpalaSS headers can work on LT1s if the collector is modified.

AA makes a great package: TC adaptor, motor mounts Headers
shift bracket etc.
but it costs moola.
Dave I dont know why u cant fit an optima under the hood, I have two.
I have a custom fuel Injection 367ci SBC that Dynoed @406hp at the crank. Ive twisted driveshafts, lotsa ring/pinions but never hurt the frame.
This kind of conversion isnt for the mechanically or financially challenged tho.
but the stoplight thrill show makes it kinda worth it.
One thing I would do fiferently tho: I did a more lopey hi rpm street cam
great for squacking the 35s, but no power till 3000+ rpm
a mild cam, manual lockout for the tranny and a heavy duty cooler will make a big difference. Also expect a cooling system upgrade

http://www.commguru.net/~owl/images/Jeep%202MUCHXJ/2muchxj_2.JPG

[jalehman]

Onetonxj,
I thought that the ls1 was lighter than the lt1. The ls1 is an aluminum block where I thought the lt1 is iron IIRC.

Also, cherokee bodies flex like crazy. I've got to get a cage built for mine before the dreaded "CRACKS" start. A friend of mine has a 94' that is literally falling apart. He's had a rear spring hanger tear off, cracks around the rear hatch and rear windows, and numerous dents form on the rear half of the jeep. Numerous spot welds are giving also. It all started with one crack around the rear hatch and started snowballing.

I don't know if two doors are a little sturdier or not, but mine is holding up a lot better than his four door. I've never had a crack yet..... Mine gets wheeled twice as much as his also. Both of us have real flexy suspension too.

[HossHoffer]

Hey owl, that is one sweet lookin' engine. I am building up an '85 myself and was wondering about what engine to go with. If I can get the bucks I might go with the 350 however I have access to a Blazer with the 4.3 including the tranny and xfer (don't know which ones yet). Was wondering what tranny and xfer case you're running in that thing.

[CW]

That is a sweet engine OWL! How much lift would I need Im at 3" and going to 4.5" soon. The engines I mentioned earlier are just laying around and and all of them are an option for me. If I drop a V8 in how big of a coil spacer am I going to need to compansate for the extra weight? I have a manual tranny, so I guess Ill need to swap that too.

[THE_OWL]

3" will be cutting it close. But actually, the 350 block is lighter than the big ole' I-6!
but I have oil pans with holes in them from hitting too hard and the front diff coming up and smashing.
Track bar might also be close. Im at 9" lift up front now and Im finally comfortable that nothing will hit it. I have a remote oil filter also. recently I went to 90degree elbows on the block side of the remote kit. Before the elbows my front driveshaft would move up and rub one of the hoses.
Crate motors are a tad pricey. If you have access, check the boneyards or build one yourself.
Vortec's are good choices. one thing I did notice about MPFI SBC engines is their lack of any soft throttle. "feathering" the throttle
is kinda tricky. My Impala SS has a LT1 with a little engine mods, it has the same issue. Seems to either grunt off the line or darn near squawk.For older blocks the Ram Horns manifolds from the seventies seem to work well for fit. Also I hear corvette shorties from the 80s work too.

Good luck!

[THE_OWL]

Oh yeah, I run a NP242 with Tera-Low, and a Super Built 700R4.
Ive had major issues with tranny cracking on the case when I went to 9" lift. Still trying to figure that out.
I dont know if AA makes an adaptor to the Manual tranny, but, I do know my owners manual says, that the stock Manual can be kept with a V8 swap, whereas the Auto needs to go
\\Hoot

[5-90]

With the slightly shorter nose of the pre-87XJ, I'd lean more toward the 4.3 swap - the front clip was lengthened in 1987 to accommodate the 4.0. It's not that the SBC swap into the 84-86XJ isn't doable, I just think that the V6-60 or V6-90 swap would be easier due to the slightly shorter engine block.

As far as engine weight, isn't the Al/Fe SBC pretty close to the Fe/Fe 4.0 anyhow? I seem to recall from somewhere that the 4.0 is a meaty - and heavy! - engine to play with. Failing that, perhaps going to a V8-ZJ coil would serve.

5-90

[BILLXJ]

,..I also have the LT1 350 V-8 ,carbureted and the Chevy 700R-4 in a 1986 XJ ,Ford Explorer 8.8. Without "flameing" anybody here,the light-weight unibody concept works well with ,in my own personal case,the addition of almost triple the horsepower (2.8 liter to 5.7 liter).My ole memory does not serve me well right now, but ANY serious student of history ,knows that the automotive predecessor of Jeep was refineing and building unibodies long ago. The question of strenght and added horsepower is simply not a concern if you're NOT particularly aggresive or overly "heavy-handed". Also you should know that there are more engine swaps done with the Chevy 350 V-8 than there are with the Ford product for some unfathomable reason.

[sidriptide]

i like the idea of the 4.3/blazer driveline myself.... get a pre-92 4.3, the vortec is not as freindly as a good ole' TBI swap.... theres my .37 cents

[4ward]

jahleman, yeah, I meant to say LT1 is only 80 lbs. heavier blah, blah, blah. I think you folks could figure that out on your own though :geesh:

5-90 was the whole front clip lengthened or just the header panel changed around? Still the same front fenders correct?????

Sean

[THE_OWL]

LT1 & Carb? is it from the early 70s?

Corvettes in the early 70s had the LT1 badge, but all new ones have MPFI.
My setup is MPFI, 8 Injectors, and a 4bbl 1000cfm throttle body.
And it is a good point about the frame holding up. Sometimes you get a Friday Afternoon Jeep and sometimes you get a Monday Morning Jeep.
I did my V8 swap in 1995! I drove it to Alaska and back with heeps of weight. I probably have 85,000 miles on this motor/setup (with 5" of lift and 33", new lift/tires was this year)

[THE_OWL]

Hear/Tell you have to cut the radiator support on pre 87'
But I dont know fer sure. Then kinda relocate it.
Mine is a 87 and I didnt have to do it

[CheapXJ]

well. I know that earlier fenders fit an 89 XJ just perfectly ;)

from what I could see by comparing the two side-by side (85 2.8L XJ vs 89 4.0L XJ), the sheetmetal immediately behind the header panel is different, and the firewall is slightly different as well. if you were to drill out all the spot welds on the core support and swap in the newer sheetmetal + massage the firewall with a BFH, it seems you could easily swap in anything, even a 4.0L!

[BILLXJ]

,.I have repeatly argued that ALL model years,.of the XJ are about the same, for example on the 1985-86 with 2.5 liter-2.8 liter engine,.the additional engine compartment space ,lenght , can be found by merely cutting off the radiator supports and a small amount of metal on the front sides with your personal choice of cutting tools,..and voila ! Position your new 3-core or Be Cool or Superior Radiator,..etc over the forward most crossmember and you are good to go with I-6, Ford or in my personal preference, the light aluminum head Chevy 350 V-8 LT1 ( the 1995,..not the 70's version)- Want to change the 86 front header panel to the 1997-02 look/design,.not a problem,..rear hatch,..,...?