4.3 Th-350/205 swap questions.....

I have been searching on here for awhile now and can't seem to find very much information on doing this swap. Im Building up my 87 MJ, putting Dana 60 front and 14 bolt rear, 4 link and 5.13s at both ends. I was originally drop in a sb305 but have now decided that fuel injected 4.3 v6 is the way for me to go. Has any body else swapped in a 4.3 th350/205 combo? The donor engine will be coming out of s10 and the tranny and transfer out of a 3/4ton chevy....Any help, hints, or ideas would be great! thanks

Do you currently have a 4 cylinder engine? If not, I can't see swaping the 4.0 for a 4.3.

I own both engines, and the 4.3 is a dog compared to the 4.0, not to mention a 4.7.

I currently have a worn 2.5l in it. I like the power of the 4.0 but not alot else about it, and length is a concern for me... The 4.3 is not set in stone, still thinking about mild small block with fuel injection.....How many small block xjs are there around here?? Got pics?

If you are set on swapping to something other than a 4.0, I would just do a very mild 350. It will be the same amount of work as the 4.3, with much more power. Dont get me wrong, the 4.3 is no slouch, i have one in a fullsize truck and it tows my jeep great, but for the same amount of work I would suggest going with the 350. However, if you do go with the 4.3, jsut be sure to get a vortec, the non vortec only makes 160 hp and 235 ft lbs of tourqe, wheras the vortec motor makes 200hp and 255 ft lbs.

There's tons of info here about 4.3 swaps and you probably should get better acquainted with the search features here. When clicking the search tab above, ALWAYS go to "advanced search" and then enter your key words in the "search forums" part. First select "search titles" to see if there's a thread specific to what you're looking for, then do the same words and select "search entire thread" which looks for the words in the narratives of the threads.

I gotta disagree with Crash on this one. I had a '91 S-10 4.3 with a 5 sp in an '84 XJ that I REALLY liked alot. So much so that I'm currently building another one and may keep that rig over the '93 XJ with the 4.0 HO that I have now. It'll be with the 4L60E or 700R4 tranny, but the flywheel with the 4.3 manual trans is HUGE compared to the 4.0 HO. I definitely noticed a huge difference in crawling - especially when from a stopped, uphill position - the 4.3 required a whole lot less RPM to get moving - and I've got the TeraLo 4:1 in my '93! Oh yeah, the S-10 drivetrain very often had the 231 HD t-case as well.

Of course, I'm talking about STOCK configuration engines here - certainly either engine can be modified to increase HP and Torque significantly, but outta the box, the 4.3 has the 4.0 HO beat......

From a Mopar site about the 2003 Wrangler's powerplant:
190 hp (142kW)@4,600 rpm; 235 lb-ft (319 Nm) @ 3,200 rpm

and comparing the older XJ engines:
'91-'95 XJ: 190hp at 4750rpm, 225lbft at 3950rpm, redline 5250rpm
'96-'99 XJ: 190hp at 4600rpm, 225lbft at 3000rpm, redline 5300rpm

From a Chevy site about the 1992-1996 4.3 Vortec with CMFI intake:
191–195 hp (142–145 kW) 260 ft lbf (353 Nm) - Max power at 4500 rpm, Max torque at 3500 rpm, redline 5300 - 6000 depending on year. The early TBI Vortecs were 160 hp.

Yeah, I know we're not talking huge differences here, but other benefits of the 4.3 are that it has a better flowing / working cooling system and lower operating temperature. My previous XJ never got above 180 deg where my '93 stays between 215 - 225 deg consistently even with a new pump, radiator, improved t-stat housing.

I'm not trying to 'dis on the 4.0 HO here, but given the option in a pre- '91 XJ, MJ.... I think the better choice is the 4.3.

No hard feelings Andy!

I'll give you the cooling for sure!

The 4.3 I have in this POS 97 S-10 (VIN Code X, as I recall) is a freaking dog.

Maybe it's the POS transmission that its bolted to,the 4L60? It's truly horrifically mushy, shifts like a Cadillac with a broken torque converter, and is always hunting for gears.

The whole truck is awful, and likes to eat electronic parts as well. Quite frankly, I have trouble discerning which part of that POS is the most awful-lest.

YELLAHEEP said:

There's tons of info here about 4.3 swaps and you probably should get better acquainted with the search features here. When clicking the search tab above, ALWAYS go to "advanced search" and then enter your key words in the "search forums" part. First select "search titles" to see if there's a thread specific to what you're looking for, then do the same words and select "search entire thread" which looks for the words in the narratives of the threads.

I gotta disagree with Crash on this one. I had a '91 S-10 4.3 with a 5 sp in an '84 XJ that I REALLY liked alot. So much so that I'm currently building another one and may keep that rig over the '93 XJ with the 4.0 HO that I have now. It'll be with the 4L60E or 700R4 tranny, but the flywheel with the 4.3 manual trans is HUGE compared to the 4.0 HO. I definitely noticed a huge difference in crawling - especially when from a stopped, uphill position - the 4.3 required a whole lot less RPM to get moving - and I've got the TeraLo 4:1 in my '93! Oh yeah, the S-10 drivetrain very often had the 231 HD t-case as well.

Of course, I'm talking about STOCK configuration engines here - certainly either engine can be modified to increase HP and Torque significantly, but outta the box, the 4.3 has the 4.0 HO beat......

From a Mopar site about the 2003 Wrangler's powerplant:
190 hp (142kW)@4,600 rpm; 235 lb-ft (319 Nm) @ 3,200 rpm

and comparing the older XJ engines:
'91-'95 XJ: 190hp at 4750rpm, 225lbft at 3950rpm, redline 5250rpm
'96-'99 XJ: 190hp at 4600rpm, 225lbft at 3000rpm, redline 5300rpm

From a Chevy site about the 1992-1996 4.3 Vortec with CMFI intake:
191–195 hp (142–145 kW) 260 ft lbf (353 Nm) - Max power at 4500 rpm, Max torque at 3500 rpm, redline 5300 - 6000 depending on year. The early TBI Vortecs were 160 hp.

Yeah, I know we're not talking huge differences here, but other benefits of the 4.3 are that it has a better flowing / working cooling system and lower operating temperature. My previous XJ never got above 180 deg where my '93 stays between 215 - 225 deg consistently even with a new pump, radiator, improved t-stat housing.

I'm not trying to 'dis on the 4.0 HO here, but given the option in a pre- '91 XJ, MJ.... I think the better choice is the 4.3.

No hard feelings Andy!

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CRASH said:

I'll give you the cooling for sure!

The 4.3 I have in this POS 97 S-10 (VIN Code X, as I recall) is a freaking dog.

Maybe it's the POS transmission that its bolted to,the 4L60? It's truly horrifically mushy, shifts like a Cadillac with a broken torque converter, and is always hunting for gears.

The whole truck is awful, and likes to eat electronic parts as well. Quite frankly, I have trouble discerning which part of that POS is the most awful-lest.

Click to expand...

Yep, that's where the 4.3 took a downward turn. Plus, the S series Blazers and Jimmys are pretty heavy, full frame vehicles - 4007 lbs and had 3:73 gears. You'll note in my previous post that those 190 HP numbers were from '92-96 model years. My wife had a '98 Jimmy and I agree with you, the trans shifts like crap - mountain drives always resulted in down / up shifts while trying to maintain a 70 mph speed.

Thanks for reminding me of the 4L60E's performance. Since my project XJ's trans is shot, I'll lean more toward the 700R4.

Im still leaning towards the 4.3. I don't dont feel i need gobs of power, going to make up for that with gearing, its more compact and lighter than either the 4.0 or sbc. Plus i can afford fuel injection for it. Rig is going to be used for trails and rocks 90% of the time....thanks for the info guys!!!!!

What years were the W series 4.3L's available? IIRC they were a 220HP engine? I believe Magoo117 installed one in his project MJ.

I'v also heard about 4.3's blowing out intake gaskets? I'v been waiting for one of these motors for a YJ i have sitting.

I just got my wife a pretty cool trail rig, 84 yota excab with a 4.3/sm465/205 It seems to run better than most stock 4.0s I've been in. I'd really be curious to see the weight difference in the two motors.

Unless you already have a 4.3 you are planning to swap in, I would strongly suggest just going with a 350.

I did a 4.3 swap in my Datsun 260Z a few years back; I have always regretted not swapping in a 350 instead. There is nothing wrong with the 4.3, it's a good motor, and is based on the 350 (the 4.3 is a shortened 350 with cylinders 3 and 4 removed), but here are my reasons for preferring the 350:

-The 4.3 won't get any better gas mileage than the 350, if the internal engine specs are the same. Theoretically it should get better mileage, but in practice it doesn't work out that way.

-The 350 will give you more power and the same reliability with less work.

-You can buy a good running 350 easier and cheaper than a 4.3, generally speaking. If you buy a motor that needs a rebuild, the 4.3 is considerably more expensive to rebuild than a 350.

-Parts are much cheaper and more common for the 350, and the 350 has a much larger selection of aftermarket parts.

-If you end up using a carburetor instead of fuel injection, the 350 is much easier to handle; partly because of the electronically controlled distributor on the 4.3's. I had to do some mix-and-match to build a HEI distributor for my 4.3 with no electronic controls.

-The weight difference is not as much as you may think; I can't remember off the top of my head so I won't thow out any numbers, but it's minimal considering the weight of the whole vehicle.

-For a tight fit (I have experience with this) the 350 will be easier because you have more options for block hugger headers, intake manifolds, etc than the 4.3. The extra length shouldn't be an issue; the 350 is only about 5 or 6" longer than the 4.3, and is still shorter than the 4.0L.

With all that in mind, I really can't come up with any advantages to installing a 4.3 instead of a 350. I put a 4.3 in my 260Z thinking that the weight difference would be worthwhile; but even in that light car (~2600 lbs) it wasn't enough difference to matter. For the amount of time and money involved in a swap like this, MOST people would probably be happier with a 350 in the long run.

If you are interested, I can scan and post up some pictures of the engine bay of my Datsun with the 4.3L installed. I think the engine bay is about the same size as an XJ engine bay, maybe a little narrower and a little longer.

Edit: One more point, if you get a newer (96+?) 4.3, it has those darn balance shafts inside it, and camshaft selection is really limited. The pre-balance shaft 4.3's have more cam choices, but also have some interesting vibrations at certain rpm's. You don't feel it so much in an OEM application, maybe softer engine mounts?, but it was pretty noticeable in my Datsun at 1800 - 2000 rpm.

I know its off topic...but in my 70' 240 ..I built a stroked 280 block with a diesel maxima crank, crank fire ignition,triple webers..etc... it made close to 310hp and still handled nicely. I had one with an LT1 the extra weight on the front end made it handle like a turd.

BIGWOODY said:

I know its off topic...but in my 70' 240 ..I built a stroked 280 block with a diesel maxima crank, crank fire ignition,triple webers..etc... it made close to 310hp and still handled nicely. I had one with an LT1 the extra weight on the front end made it handle like a turd.

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Cool. You can do a lot with those Z-car sixes.
Was the LT1 set back all the way against the firewall, and was the front crossmember lowered to set the engine down low? Those two things are the key for V8 handling in a Z-car, or any car for that matter. Even an all-iron small block mounted right in a Z-car can improve the cars balance by shifting more weight to the rear to get 50-50 weight distribution, or even more to the rear if you want.

zthang43 said:

Cool. You can do a lot with those Z-car sixes.
Was the LT1 set back all the way against the firewall, and was the front crossmember lowered to set the engine down low? Those two things are the key for V8 handling in a Z-car, or any car for that matter. Even an all-iron small block mounted right in a Z-car can improve the cars balance by shifting more weight to the rear to get 50-50 weight distribution, or even more to the rear if you want.

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yes to all of the question..I pretty much copied a factory prepared Scarab car. It still was subpar handling compared to the one set up with the 3.2 6cyl.