Anyone running a 4.3?

[mikep]

Looks like it might make a good easy swap for better gas mileage. Iv'e driven a few later model trucks with 4.3's in them that I swore were small blocks until I opened up the hood. I'm sure you'd have to move the radiator back a bit but other than that it looks really straightforward. Mounts the same as a small block and the accesories are all the same.

[Hooter]

would be a good idea though. A strong 4.3 has got some balls. they are basically a 350 with two cylinders cut off. I sure would like to see a creation like this maybe with a turbo or something would be cool

[JJ]

Great idea Mike, I've been wondering if it would be possible to take the 4L60e and all. It's a great combo in my Astro van. The weight couldn't be that much different, and it gets about 22mpg.

[Longhorn Man]

Just stay away from the early CPI ones....they are great when they run right, and very expensive when they go tits up.
It would be alot of work, and no where worth the effort IMO.
But, that may well be just me.

[Dropt72Shortbed]

i agree with longhornmail on this one.

the highest rating for the TBI 4.3s was 165hp i believe.
the CPI units had 195hp and were the most powerful right out of the box, however the cpi unit is prone to leaking at low mileages and the parts on these are pricey.
the 96+ 4.3s are all SFI and are 180hp out of s10s, 190hp out of astros, blazers, 4x4 s10s, and 200hp out of fullsize trucks.

for the price of all that you could just go but yourself a crate 350 for $1400 with 250hp and a 3yr/50k warranty.

also dont kid yourself on 4.3s getting good gas mileage, ive had 3. and my gas mileage average from all 3 is around 15.5mpg. mind you these were all from s10s and blazers. these trucks are heavier so id expect less mileage that what they get in s10s.

id rather take a stock 350 and th350 and get 13mpg..

[XXL]

Originally posted by Dropt72Shortbed
the highest rating for the TBI 4.3s was 165hp i believe.
the CPI units had 195hp and were the most powerful right out of the box, however the cpi unit is prone to leaking at low mileages and the parts on these are pricey.
the 96+ 4.3s are all SFI and are 180hp out of s10s, 190hp out of astros, blazers, 4x4 s10s, and 200hp out of fullsize trucks.

What about the Syclone/Typhoon 4.3's? Stock, I think they were around 280hp. And I know some guys out there are realy jacking them up with bigger turbos and lots of boost. I seriously considered this as a transplant option myself... the biggest trouble is finding a donor.

Kenneth

[Dean]

I have a 4.3 in my Chevette Pro Street/Drag Car. It is quite a handfull, but a Chevette doesn't weigh very much. It is backed up by a Turbo 350 trans and a narrowed 9" Ford rearend. The engine is obviously no where near stock....bored out to 265 cu in, Lunati roller cam, Brodix aluminum nascar heads, Brodix high rise intake, gear drive, 12.5-1 compression, headers, electronic ignition.....etc. You have to run it on racing fuel though. Barely streetable for a short trip.

Eldebrock makes a nice aluminum four barrel intake for a mild street engine. I used to have one, but it wouldn't fit the Brodix heads.

Those 4.3's won't take a lot of high RPMs unless some major work is done on the oiling system also.

I think I would stick with the 350 unless you just happen to have a good free 4.3 and you need the transportation.

[yellowgmc]

check out either hot rod, car craft or chev high performance (not sure which one all my issues are at work). last month they put a supercharger on a 4.3 and got 501hp out of it. crazy boost though. somewhere around 12psi.

[mooneyes]

hey dean whats the chevette run in the 1/4 ?...sounds like a neat little ride

[tom hand]

My 2003 S-10 knocks down 18+ mpg in the city all the time. It would be a simple bolt in swap and still have some pep. If you got a radiator shroud from a full size pickup the radiator can stay in the stock postion. The early ones came from the factory with quadrajets if you don't want to play with computers. Go for it.

[Zkast]

I agree with Dropt72Shortbed on this one..

Aside from doing all the electronics conversions, mechanical conversions and buying all the parts, you would have a setup thats going to give you less than desirable results. The reason I say that is this:

The 4.3 in a S10 pickup is quite impressive with 180hp and the small wieght of a mid size truck. Now take the same engine/trans combo and shove that into a 3900lb full size older truck and you have just killed the torque in that engine. It may perform ok and will definatly be more consistant with Fuel Injection BUT and this is a big BUT, you'll be killing the gas mileage try to get a v6 to move the heavy ole truck. With the 4l60e and a 4.3 in a full size truck, its going to be a battle to keep the trans in overdrive while on the highway. It just doesn't have enough torque to pull a truck this size. GM keeps trying to put these v6's in the full size truck.. EVEN 4x4 and the same result keeps coming up, low power.

The older design with a quadrojet on it was horrible on the highway. People were constantly bringing their full size trucks in for low power/performance problems. Same result, v6 in a full size truck. I dont mean to sound like im bashing the 4.3, not at all, but they have thier place. small to mid size car/trucks work great. Not in a heavy truck that may tow at some point.
Stick with a well built 350 and a 700r4 and hope for 15mpg

[JJ]

My reply is not based on theory, or horsepower on paper. I have a 1993 Astro van with a 4.3 engine and a 4L60E transmission. My observations are based on the following. The van weighs quite a bit more than an Blazer or S-10 pickup. I get between 19 and 20 MPG on an average tank of local driving. When I travel I get closer to 22-23 MPG. The vehicle has plenty of power, and it tows just fine. If my memory serves correct these trucks came with a 250-6 cylinder, and they were just fine as a powerplant.
I think if you're wanting to build a high performance vehicle this would not be the engine for you, but if you're wanting to build a commuter/daily driver it would be just fine, plus the mileage would be almost double what you get with the 350.
I have a 4.3 Vortec with 600 miles on it out of a 2001 pick-up, the owner had issues with the engine, so the dealer swapped it out. I'm seriously considering putting it in my daily driver. I'm not racing anyone anymore, I'm interested in reliability and mileage now.
Does anyone get over 20 MPG with their V-8?

[TODDS 72]

I like the 4.3s,have had proll4or5 of them 3 in 1/2 tons and s10s.
I get bout 16 all around with the s10 bout 18 on the highway.
In the 1/2 tons got bout 15 ,these were all standards.
In my K10 5.7 700r Iget bout 16 on a trip .
the ones that have the most problms are the W engines with cpi,
the Z engines are just TBI.
So you might as well get a good 350 from JASPER with 3/75000
warrenty,and a good 700r to back it up .

[mikep]

Of course the original question being would this be a good swap for better gas mileage. I would get more power out of a 350 ... Duh. I know that. I have a 350 and it has plenty of power but I also know that I get 13 miles per gallons if I drive really slow and am about to have to start commuting over 100 miles a day within the next year and I'd like to keep my truck. I also have a complete 4.3 I am considering rebuilding with vortec heads . Original 67-72's came with 250's and ran just fine with them. The 4.3 actually has more displacememnt and has better parts availability , Ive driven quite a few full sized late model 1/2 ton 4speed auto 4.3 equipped trucks that got great mileage compared to my truck and still had good power for a full sized truck. I'm not talking about a turbo, intercooled, fuel injected 6 cylinder monster. That would be silly. For the same money I could build a big HP big block that got the same mileage and had more power. I'm talking about a truck set up to get good mileage and have enough power to get out of its own way and thats about it. I think the 4.3 can do it. I'm not saying I am going to do it but its an idea I am considering. Because of my parking situation I cant really get another vehicle and the wifes 2002 Ford ( whatever that thing is) is her car and she can have the damned thing . If I have to make my truck a hiway star then thats what I have to do. I have a year to think about it.

[Zkast]

Lets say you've decided to go for it... Would you put a automatic or standard? And would it be fuel injected or carb'd?

With a auto/carb and the full size truck you wouldnt gain speed on a good size hill, you'd be able to maintain that speed.

The majority of what I see in the shop (as far as full size 4.3L equip) they will all have 5speed's behind them. Van's and midsizes are different though. That alone give's them the feel of decent power.

[Gee_Emm]

My Dad had a 96 Jimmy with a 4.3 and then he went up to a 99 Denali and he hardly noticed a differnence in gas mileage, maybe 1 mpg more


And the Denali isnt exactly light weighing in at over 6000 lbs.

[Longhorn Man]

The Sy/Ty trucks were 3.8 with a turbo...Grand National set up.
I speak from 6 years of driving a 92 S-10 Blazer Tahoe with the W code (CPI) 4.3 vortec....
I'd rather have the inline.
MPG in our autooverdrive is in the upper teens, and it does have gobs of torque...until about 1300 RPM, then it falls on its face. Once you hit 2500 RPM, it is wheezing for air like the kid whith azmah (I know I mis spelled it) trying out for the track team in high school.
There was very little that impressed me on this rig, it was like Clinton....over promised, and under delivered. I am amazed it is still on the road with only 145K on the clock.

[XXL]

Originally posted by longhornmail
The Sy/Ty trucks were 3.8 with a turbo...Grand National set up.
.

I beg to differ. Sy/Ty's are 4.3L 90 degree V6's.

Here's

Edmund's Guide information and here's an article from Turbo Magazine on the truck, both of which agree.

Kenneth

[Zkast]

Maybe im misunderstanding? the Denali (pricey Yukon) was 5.7L 255hp AWD getting 13/17mpg at best. In '99 that is...

[Stano]

Syclones and Typhoons had 4.3's I agree. My girlfriend/wife now had a 92 fullsize 2wd 1/2 ton when we were in highschool and we kept it for a couple years after we were married. I was/ am a speed freak and that truck impressed me alot with the 4.3 and 5spd. We took it on a trip and went 500+ miles on a tank of gas and it would roast the tires til you let up. I miss that truck still. How cool is this, married a chick with a nice new truck and we took the 67 on our honeymoon. LOL

[Palf70Step]

I had a 92 Chevy 1500 short bed 4.3 V6 with 5 speed. Thought it was great for what I did. Haull my butt and not much more. Down south I average about 19 around town with A/C on most of time. Best I did on road was 25, in Colorado Springs. It seemed to run better at elavation than at sea level. I though with the stcik it was great, but my firends had an automatic. not sure whihc model. Whatever they used in 92 with oD. A Dog in my book. Would have hated it any whaere that is not flat. A guy at the church had an extended cab w 4.3 auto. I don't know how it moved.

I think 4.3 w/ 5 speed be good combo if it was a daily driver, but not hauler. Although, my 250 I6 has/feels like it has a lot more guts. I think that's why Chevy went back to the I6 design. More torgue per CI than a V model engine.

theres my $.02

[Dropt72Shortbed]

Originally posted by JJ

Does anyone get over 20 MPG with their V-8?

now this may just be because im in CA and we have piss for gas but i DONT GET CLOSE to the 19-20mpg youre reporting on your 4.3, and my vehicles were all lighter than your astro!

94 s10 reg cab 4.3TBI(165hp) 4l60e 3.42s got 17mpg
97 s10 ext cab 4.3SFI(180hp) 4l60e 3.42s got 15mpg
01 2dr blazer 4.3SFI(190hp) 4l60e 3.42s i only get 15mpg

i do not drive with a lead foot (kinda impossible with southern california traffic.) the window sticker said 17-23mpg on all 3 of these. now im averaging 15.66 mpg here, i do about 50% city and 50% freeway (drive at 75mph) according to the sticker i should be getting somewhere in the middle, say 20mpg.

my moms 02 trailblazer gets less mpg than the sticker as well, my dads 01 GTP gets less than the sticker, my sisters 94 civic gets less than the sticker.

are these mpgs on the window stickers based on the whole US? cause i guess using CAs gas would then be the reason for all my past and present vehicles, as well as my parents, all getting less mpg than they were supossed to.

[Longhorn Man]

Wow...Sorry.
I colda sworn...
Oh well.

[mikep]

actually my goal is to find a job either closer to home or in an area I want to relocate to before my company moves next year. I dont relish an hour and a half commute each way every day through tacoma narrows bridge traffic. That way I wont have to go through with this stupid plan!

[Dean]

You probably thought it was the 3.8 Grand National engine in the Typ/Sycl. because it was the Buick design engineers that did it. It was the 4.3 though. I guess they had nothing to do at Buick so they jumped over to the trucks.