4.3L "Baby LT1" V8

[NeonLX]

Heh. Remember the Olds 260 "Baby Rocket" V8?

I was always amazed at the Ford 221 V8 that came out 1962-ish. That particular mill always seemed happier in 289 or 302 guise.

[Drew Dowdell]

A small displacement "Small Block" is not really a good idea.

Not that a small displacement V8 is necessarily a bad thing, but the small block's 111.76 mm bore center is really better suited to something around 5.5~7.0 liters, not 4.0~5.0 liters. The 4.3 had a 95 mm bore, that's almost 17mm of metal between each cylinder. This is completely unnecessary for strength. It also makes the engine unnecessarily big and heavy (a lot of useless metal) for a 4.3 V8. If the idea is to create a 4.3 V8, a 102 mm (same as Northstar) or 103mm (same as 3.6 HF V6) will be a better choice. These will yield a smaller and lighter engine. Make a small block displace that few cubic inches, is like deboring and destroking a 3.6 V6 to 2.4 liters. You'll end up with a 2.4 liter engine that is heavier and no smaller than the 3.6 while making less power and torque.

They came pretty close to that when they made the 2.8 HF

[G. David Felt]

Small is not always better, The Mazda K8 V6 1.8L comes to mind with it's numb numbers of 144hp with 115lb-ft of torque and 7000 red line. Personally this was a cool engine for how small it was but showed that more is not always better in the cylinder count.

I would think we could find the perfect sweet spot for the size of 4, 6 and 8 cylinder engines.

[NeonLX]

From my farming experience, I know that cylinder count isn't always better, and is in fact sometimes worse when considering more heavy duty applications like tractors used for tilling ground. Back in the 1960s-70s, some manufacturers began installing V8 diesel engines in tractors. In most cases, they were large displacement mills (the Cummins 555 and 903 CID V8s come to mind here). At the same time, other manufacturers stuck with large displacement, inline six diesels (Cummins had an 855 CID six, and I remember John Deere's 619 CID six as well). From my experience, the V8s put out their rated horsepower at a higher RPM than their six-cylinder counterparts (something like 2800 RPM vs. 2100 RPM), and they also lacked the lugging ability of the sixes (torque curve was peakier, maybe, or the torque rise wasn't there). I remember operating a big Versatile 4X4 tractor powered by the 903 V8 circa 1975; the thing would bog down a lot more easily than a Steiger tractor with the 855 Cummins six. I don't claim this is any kind of scientific analysis; it's just my experience from back in the day...

Edited October 10, 2012 by NeonLX

[Guest Heavychevy]

I just bought a 96 caprice classic with a 4.3 v8 and did a little digging, its externally identical to the lt1 except the bore and stroke are different. It was standard option 94-96 (four larger v8s were optional). Wikipedia.

[Guest michael wright]

I own a 1996 chevy caprice with the 4.3 V8 and love it i have 165742 miles on it and still runs strong

[Guest Guest]

I have a 77 caprice coupe but im having issues with my 96 caprice 9c1 (ex cop car ditectives unit) with the 4.3l i just bought it at 88 thousand miles.

Seems to run well but I had dual exhaust added,straight duals no cats to flowmasters and now after a few weeks it's idling very high but only under load,

If I'm at the lights on the break it's pulling forwards if I slip in to nuteral it revs up for a few seconds then levels out to a normal idle

Just wondering if anyone thinks these problems could be related to the exhaust change?

Also with these changes do I need to reprogram the computer?

Thx to any one that can help

[Guest Sharman]

I have a friend who has that exact motor in a 94 caprice. It really is a baby Lt1 which is in my 96 caprice...I think most of those cars went to the police, but it wasn't stripped of the door panels, rubber'd floor, and lights..just used as a detective or officer's car...

[Guest Bob O]

I have never been able to understand why auto companies have a good thing going and then abandon it. If it aint broke don't fix it rarely applies for some reason. Do they WANT to lose money and business ? Reliable with great gas mileage doesn't get old. You would think they actually believe buyers prefer unreliable gas hogs.

[Guest Robbie]

Ive got one I swapped into a S-10. Has a stock 5.7 camaro cam, headers, megasquirt is running the fuel...Optispark is crap..drilled a hole in the intake and put in a short distributor. Ready for some boost

[Drew Dowdell]

Probably can be over-built relatively easily.

[Guest brandon]

OK....so I'm flipping through some old C&D rags and in the 10-93 issue, highlighting the "1994 New Cars" there was an article in the Technical Highlights section talking about GM's new "baby" LT1 variant....a 4.3L version that would be the base Caprice Classic engine along with the optional 5.7L LT1....

Does anyone remember this engine? I don't even remember it existing.....and surprised we didn't see it in other applications (might it have fit tranversly in a GM-10 of the time??)

Here's how the two engines compared:

4.3L, SFI V8 (5.7L SFI V8)

200 hp (260 hp)

245 lb/ft torque (335 lb/ft torque)

Let me know if you know anything about it...!

i actually have a 1995 caprice classic, and yes it has a 4.3 v8 also knows as "the baby ls1"

[A Horse With No Name]

Sweet!

[Guest seth]

I run the 4.3 in my 1994 caprice classic sleeper with a mild cam valve springs and stall along with 4.11 rear gears and a custom ecm tune it leaves mustangs at the line wondering how a 4100 pound boat just smoked them. Prefur the torque curve of the 4.3 over the 5.7 it seems too pull threw the high side of gears better

[Guest William C Murphy]

In 1982 I ordered through a Pontiac Buick dealer in Ontario Canada a 1982 Pontiac Grand Prix LJ or SJ with a v/8 gas engine, and it was a 267 cu.in. displa.

[Guest craig]

the crank would be perfect in a 350 hydraulic roller block to build a 302, add a turbo or two...

[Drew Dowdell]

Can the cylinder walls handle it?

[Guest Bdover]

I bought two caprice classics a few months back. One is a 94 and the other a 95. They both have the 4.3 L99 in them. I sold the 95 because of body condition and have been restoring the 94. 156,000 miles and that little v8 runs like a top and since putting true dual exhaust and bullet mufflers on has a little get up and go to it. I'm getting ready to put a stage 3 performance chip system in it that supposedly will give me an extra 100 lbs ft torque and 40-60 more horse. I'm curious to see how she performs afterward but overall am impressed with the baby LT1 already and had my doubts when buying them.

[Guest Keno]

I have a 94 Chevy caprice classic with the 4.3 and I was trying to see how can get mores horsepower

[G. David Felt]

I highly recommend Jet Chips. They really give GM small Blocks some amazing improvements over OEM Chips.

http://jetchip.com/

[Guest JT Lambert]

I think ya'll are missing ,that GM shaved two cylinders off of an LT1 V8 and made a bonzi 4.3L LT1 V6.Guess who used it......GMC in the CYCLONE and another model.Both models were AWD.They were turboed and well over 400hp with scads of torque.

[Guest 95 4.3 Caprice]

GM did make a 4.3L. V8. I happened to own a 1995 Chevy Caprice with that engine its ok for everyday driving but as far as raw power and torque it doesn't have that the only time you may spin a tire is in loose dirt or wet pavement.

[Stew]

4.3 was also sedan only, all Caprice Wagons from 94-96 came with the LT1.  I had a 96 Caprice LT1 and a 96 Roadmaster LT1, miss them both.

[Guest Andrew]

I'm picking up an 86 Monte Carlo that has this exact motor in it. 4.3 EFI V8. It's a pretty engine, and even rarer swap, but it does exist. 

[G. David Felt]

I think ya'll are missing ,that GM shaved two cylinders off of an LT1 V8 and made a bonzi 4.3L LT1 V6.Guess who used it......GMC in the CYCLONE and another model.Both models were AWD.They were turboed and well over 400hp with scads of torque.

 

Yes GMC use their Turbo V6 in both the Syclone and the Typhone. Syclone was the awd pickup truck and Typhone was the compact awd SUV.

[FordCosworth]

I think ya'll are missing ,that GM shaved two cylinders off of an LT1 V8 and made a bonzi 4.3L LT1 V6.Guess who used it......GMC in the CYCLONE and another model.Both models were AWD.They were turboed and well over 400hp with scads of torque.

 

 

No. They were not well over 400HP.

 

And the 4.3L was not based off the LT1. The 4.3L V-6 came out in 1985. The same year as the L98

 

There was no LT1 in 1985 to base the 4.3L Vortec off of.

[G. David Felt]

 

I think ya'll are missing ,that GM shaved two cylinders off of an LT1 V8 and made a bonzi 4.3L LT1 V6.Guess who used it......GMC in the CYCLONE and another model.Both models were AWD.They were turboed and well over 400hp with scads of torque.

 

 

No. They were not well over 400HP.

 

And the 4.3L was not based off the LT1. The 4.3L V-6 came out in 1985. The same year as the L98

 

There was no LT1 in 1985 to base the 4.3L Vortec off of.

 

The Syclone was rated at 280HP 350 pounds of torque. 

 

The Typhoon was 280hp 360 pounds of torque.

 

Yet with aftermarket parts they could go over 800hp.

[Guest Travis]

I own a 94 caprice classic the 4.3 v8 is very real that's what came in mine factory very reliable motors...and actually have some power for bein so small displacement and a heavy car...

[Guest Travis]

I run the 4.3 in my 1994 caprice classic sleeper with a mild cam valve springs and stall along with 4.11 rear gears and a custom ecm tune it leaves mustangs at the line wondering how a 4100 pound boat just smoked them. Prefur the torque curve of the 4.3 over the 5.7 it seems too pull threw the high side of gears better

[Guest Travisk1987]

I own a 94 caprice classic with the 4.3 v8 very reliable mptor & has good power considering the size of car & how small motor is...

[Guest [email protected]]

OK....so I'm flipping through some old C&D rags and in the 10-93 issue, highlighting the "1994 New Cars" there was an article in the Technical Highlights section talking about GM's new "baby" LT1 variant....a 4.3L version that would be the base Caprice Classic engine along with the optional 5.7L LT1....

Does anyone remember this engine? I don't even remember it existing.....and surprised we didn't see it in other applications (might it have fit tranversly in a GM-10 of the time??)

Here's how the two engines compared:

4.3L, SFI V8 (5.7L SFI V8)

200 hp (260 hp)

245 lb/ft torque (335 lb/ft torque)

Let me know if you know anything about it...!

i actually have a 1995 caprice classic, and yes it has a 4.3 v8 also knows as "the baby ls1"

[G. David Felt]

 

 

OK....so I'm flipping through some old C&D rags and in the 10-93 issue, highlighting the "1994 New Cars" there was an article in the Technical Highlights section talking about GM's new "baby" LT1 variant....a 4.3L version that would be the base Caprice Classic engine along with the optional 5.7L LT1....

Does anyone remember this engine? I don't even remember it existing.....and surprised we didn't see it in other applications (might it have fit tranversly in a GM-10 of the time??)

Here's how the two engines compared:

4.3L, SFI V8 (5.7L SFI V8)

200 hp (260 hp)

245 lb/ft torque (335 lb/ft torque)

Let me know if you know anything about it...!

i actually have a 1995 caprice classic, and yes it has a 4.3 v8 also knows as "the baby ls1"

 

Yup the family had a couple of these, all retired and long gone but was a solid baby V8

[Guest bill]

I on one i drive everyday it a good car they also put that motor in fire birds and cameos has good torque and good top end speed

 love my caprice its a 1994 model

  

[FordCosworth]

I on one i drive everyday it a good car they also put that motor in fire birds and cameos has good torque and good top end speed

 love my caprice its a 1994 model

 

 

The 4.3L L99 was never available in a Camaro or Firebird 

[riviera74]

Is this LT1 being used today? And in which models?

[Guest Oltomkat]

I actually have one. Put it in my CJ7. It does great.

 

[Guest carguy]

It was produced. A friend of mine had one and it was very smooth but not very powerful yet a far better engine then the previous 305CI 5.0L V8 in the Caprice. Like the first SB V8 it was 4.3L's and 265CI!

[Guest Christopher Taylor]

Is this LT1 being used today? And in which models?

No. This is based on the original reverse flow cooling SB Chevrolet V8. Todays SB V8 is very different. They reuse names every 25 or so years for the performance versions of the SB V8.

[trinacriabob]

It's funny that this thread recently woke up again.

A B-O-P service adviser told me about this engine.  It was in a Chevy they sold on their used car lot and they then had to service it.  He couldn't believe it either.

At any rate, I then became interested in these 4.3 units, seeing how much I liked the Olds spin on their V8 (theirs was a debored Rocket 350 back in the day).  That one was known for its quiet operation and longevity.  So, I found a few on used Caprices of '94 to '96 vintage on used car lots with this engine.  Upon turning the key, this engine has a beautiful purr (nicer than any 5.0 or 5.7 I can remember) but I didn't want to drive it because I knew I wouldn't be buying it.  With a serpentine belt and electric fan(s), this thing set up as RWD is a mechanic's dream.  

I've even talked to a few owners.  They love their Caprices of these years.  One was a Kentuckian who had taken it down to Florida for vacation.  It had about 300,000 original miles on it and he told me he can break past 25 mpg on the open road.

I don't think I'll ever do the second car thing again.  However, if I did, this would be it.  I've looked at EBay and other sites.  It's hard to find one in a nice color, in good shape, with cloth seats (leather has all these cracks after all this time), and reasonable mileage.

I know that their 80's 4.4 displaced 267 cubes.  I think cubic inches had fallen out of favor by the time this engine rolled around.  It would be interesting to know how many c.i.s it displaced.

 

[trinacriabob]

More info:  L 99 - displaced 263 c.i. - born of the Chevy 5.0 L / 305 c.i. - no change in bore but change in stroke - 200 h.p., even, and very good torque - over 25 mpg on highway EPA rating - only produced for 3 years and for the sedan (not the wagon), so not an omnipresent engine in the Chevrolet stable.  Very interesting, at least to me.

[liketowin77]

94, 95 and 96 Caprice ONLY. Go to Rockauto.com and look them up, they are there. They are an L99 and they are NOT the same as the MONZA engine. The MONZA had a different bore and stroke. The L99 has a 3 inch stroke, same as the 283 and chevy 302. As a matter of fact, you can take the crank and put it in a 350 block and you'll have a true chevy 302 just like in 1969 except it will have the one piece rear main seal. Just make sure you use the L99 connecting rods with whatever 350 pistons you want. That's all Chevrolet did, they put a 283 crank in a 4 inch bore block and made a 302. A Ford 302 is the same bore and stroke as well. 

[trinacriabob]

On 1/1/2018 at 5:27 AM, liketowin77 said:

94, 95 and 96 Caprice ONLY. Go to Rockauto.com and look them up, they are there. They are an L99 and they are NOT the same as the MONZA engine. The MONZA had a different bore and stroke.

Every once in a while, I go onto eBay or craigslist and look for these Caprices ... in base form and with the 4.3 liter V8.  If you think they come by cheaply, they don't.  Far from it.  What you'll see is one that is in dire straits and on its last legs sitting in a corn field in a small town in southern Illinois where there are fewer teeth in the town than there are cubic inches in the engine, and they're asking $795 or less, and it has been sitting there for a long time, looking like the Andrea Doria accumulating plankton.  Then, you'll see one in immaculate condition with 60,000 miles and they want anywhere from $5,500 to $7,000.

Within the past 4 months, I was at a light next to one.  I rolled down the window and so did the passenger.  It was burgundy, had whitewalls, factory spoke wheels, and a burgundy leather interior.  The husband beamed that it had less than 45,000 miles.  I asked which engine it had.  The wife, the passenger, looked at her husband and he said it had a V8.   I knew that.  The light changed, so I couldn't ask more questions nor ask if he'd sell it.  I'm betting it had the 5.7 liter V8.

[Johnny]

On 1/7/2016 at 5:26 PM, FordCosworth said:

 

 

No. They were not well over 400HP.

 

And the 4.3L was not based off the LT1. The 4.3L V-6 came out in 1985. The same year as the L98

 

There was no LT1 in 1985 to base the 4.3L Vortec off of.

 

[Johnny]

1978

 

The 4.3L Chevy V6 is among the strongest of production V6's ever produced, especially in its later versions. It was first produced in 1978 and that design stemmed from the 1955 Chevy Small Block V8.

 

The Novak Guide to the Chevrolet Small Block V6 Engine

Had Several ofn these cars, during my quest for one of them, I came across a 1994 (this was in 2006) former NYC police car, former NYC taxi, 557,000 miles. With regular maintenance, these were tough cars.

 

[ehaase]

I remember the 4.3L V6 debuting in 1985, but Chevrolet first V6 based on the small block V8 was a 200 cubic inch version that debuted in the downsized 1978 Malibu.  It was upsized to 3.8L in 1980  229 cubic inches (full size cars still had the 250 inline six as standard for 1977 through 1979), which was standard in the full size models and then upsized again in 1985 to 4.3L.  I remember having driver's training in a late 70's Malibu with the 3.3.  It could barely go up a hill. 

[trinacriabob]

On 8/2/2020 at 1:43 PM, ehaase said:

I remember the 4.3L V6 debuting in 1985, but Chevrolet first V6 based on the small block V8 was a 200 cubic inch version that debuted in the downsized 1978 Malibu.  It was upsized to 3.8L in 1980  229 cubic inches (full size cars still had the 250 inline six as standard for 1977 through 1979), which was standard in the full size models and then upsized again in 1985 to 4.3L.  I remember having driver's training in a late 70's Malibu with the 3.3.  It could barely go up a hill. 

A lot of good facts here and with all the low 3 liter V6s and 4.3s in both V6 and V8 form, it's easy to get them confused and/or forget them.

I had forgotten.  There was a 3.3 V6 in the downsized Malibu because, that same year, they put out a 3.2 V6 (196 c.i.) for equivalent Buick products, such as the Regal and the Century.  I knew someone who had this engine in a hand-me down in a 2-door Regal, and he said it was reliable, economical, but had no oomph.

It was great that Chevy's downsized full-sizes kept the inline 6 because the engine bay had room for it.  I believe 231s were available in the BOP full-size base cars.  I think, in that era, I'd opt for the inline 6 over the 231.

I don't know what the 4.4 V8 was based on, which was also found in Malibus and Monte Carlos.

4.3s by Chevrolet can be confusing, since they made them as V6s and V8s.  Both were excellent engines. 

The 4.3 V6 (Vortec) was sliced off from a Chevy 350.  Who'd have thought that this engine was a slam dunk for 300,000 miles?  A few Astro van drivers have told me that their 4.3s would not give up the ghost.  I think that, in that era, the 4.3 V6 (~ 262 c.i.) with simple TBI was better than the 231 c.i. V6, even if the 231 had gone even firing.  And, yes, it showed up in the 1985 MY model year.  I had the opportunity to drive a RWD Monte Carlo (bucket seats and console!) coupe with that engine in the NYC area and the extra ~ 30 hp (if I recall) came in handy for short ramps and getting out of the gate after paying a bridge toll.

The 4.3 V8 was a de-bored 5.0 (305 c.i.) V8.  It showed up for the 1994 MY in RWD form but only stuck around for a few years.  If in excellent condition, the purr that they make is music to the ears.  It also can go the distance ... just hope the Optispark ignition control doesn't give out, which can be costly.  For some reason, the smaller GM V8s have nice, quiet exhaust notes and I like quiet running cars.

Also, in the late '70s, Chevy had some batches of 305s and 350s that had premature camshaft wear problems.  I knew a few people who had problems with them.  That definitely skewed me towards Olds designed V8s.  However, with all of that behind them, I would gladly drive a car powered by the L99 engine (4.3 Chevy V8) that the thread discusses.

 

Edited August 8, 2020 by trinacriabob

[A Horse With No Name]

4.3 V6 is a running motor. 

[trinacriabob]

On 11/27/2020 at 8:37 AM, A Horse With No Name said:

4.3 V6 is a running motor. 

Right. It lives on. An acquaintance has it in a basic Chevy truck. Like the last 5.7, it would be an all aluminum (block and heads) unit.

[A Horse With No Name]

1 minute ago, trinacriabob said:

Right. It lives on. An acquaintance has it in a basic Chevy truck. Like the last 5.7, it would be an all aluminum (block and heads) unit.

I thought all 4.3's were iron block....I could be wrong. 

[trinacriabob]

4 minutes ago, A Horse With No Name said:

I thought all 4.3's were iron block....I could be wrong. 

I looked up the stats on this 2017 and 2018 truck and it was aluminium. I, too, was surprised. If a mainstream car maker is making an all cast iron engine for a vehicle at a good price point, someone needs to let me know!