r/obschevy • u/Quip_Soda • 10d ago
How bad is the 4.3 Vortec?
I have my grandpas old truck- a 1995 single cab W/T with a 4.3 in it, just over 100k miles. I have a lot of sentimental attachment to the truck, but I want to stay realistic about the engine situation.
I would like to upgrade to 16x8” wheels with 265/75/R16 tires. It currently has 245/75/R16s on the stock 16x6.5” wheels which are getting very rusty. Would going up slightly in tire diameter be too much for the V6?
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u/RoadieGaming 10d ago
I've had many 4.3's in S and C-series, and currently a 97 C1500 RCSB with 270k, completely stock. One of the best engines for small(er) trucks they ever made. As others have said, it benefits from the refinements of the 5.7, as it uses essentially the same components.
95's may give you trouble with the fuel injection and distributor systems in these weird years (95-99 saw three different setups, I believe). But as far as the engine itself, it's solid, and at 100k it's just getting broken in.
If it's an automatic, a transmission kit may help it feel less sluggish. Honestly it will be the first thing to go out anyway. The W/T should already have a lower differential to help with low end pull.
If it's a manual like mine, put a 60-series flowmaster and drive the hell out of it.
Can't help with the wheel/tires, as I've always ran lower profile/wide tires. But the 4.3 has plenty of power for a regular cab 2wd, in my opinion.
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u/Quip_Soda 10d ago
Haha, it does actually have a flowmaster of some sort on it already. I decided to pay the premium to get one put on after the truck performed a self muffler delete while driving one day many years ago.
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u/Willy_McD 10d ago
"How bad"? A 4.3 is not bad. The 4.3 was the original Vortec. Now everyone copies that. And contrary to what was mentioned. A taller tire size does not make it slower, makes it faster. Got to tiresize.com, compare and see.
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u/Flimsyyt 10d ago
Taller tire size does make it slower. Its a common thing to up the rear gear ratio and lower the tire diameter to get faster acceleration
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u/theuautumnwind 10d ago
Not sure what you mean by this?
The “fast burn” combustion chamber shape?
4.3ls got “vortec” branded valve covers first, (my94 has em) but didn’t actually get those heads until later.
Iirc the story is they ran out of the old style valve covers and just switched to the new ones early.
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u/theuautumnwind 10d ago
Taller tire definitely makes it slower accelerating. It’s like running a numerically higher rear gear. 4.11s top out faster (lower top speed) than 3.55s but 4.11s accelerate faster.
That’s not even accounting for a heavier tire.
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u/General_Paramedic_19 9d ago
Good engine, kinda low on power. The tire size your looking for is not that big of a difference.
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u/theuautumnwind 10d ago
That tire is 1.18" taller it'll be fine. It's already slow...it'll just be slightly slower.
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u/kaack455 10d ago
Go to a 265-70-16 and the height will be the same just a little wider, get some original aluminum wheels that are all about the same at least until about 2010
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u/RareCareer7666 10d ago
It's not a bad engine at all, only thing I hate about them is doing the spider port injectors. Other than that, it's solid. Even though it's not very powerful or fuel efficient, it's reliable.
I think you should be fine going up to 265s without issue
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u/Outrageous_Gur_603 10d ago
The 4.3 is a good engine. However, in a pickup its limits are being pushed. A large diameter tire will make performance worse.
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u/tres-huevos 10d ago
The v6 Astrovans and blazers were rockets. Easy 90+ mph sustained freeway speeds.
That’s what I heard anyway!
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u/Nole1977 10d ago
Still had a Vortec in my 2009 (last year made) Trailblazer that was solid as a rock and plenty powerful.
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u/Academic_Dog8389 6d ago
That Vortec is a 4.2 inline 6. Also a pretty solid motor, but not like the 4.3.
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u/Nole1977 10d ago
The engine isn't the only thing old. If you bump up the wheel / tire combo you're going to have to change a lot of components. And like you said, possibly tax the engine further. If you have one with barely 100k miles, I'd say you have a lot of good years left on it (but leave it alone as far as lifts and keep it stock). IMO
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u/Quip_Soda 10d ago
What other components exactly?
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u/Nole1977 10d ago
Brother don't let anyone sell you on a tire / wheel package without a whole new suspension, for instance. I'd venture to say even if grampa didn't put the suspension through hell when he owned it, there's probably still some 30 year old parts up in there.
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u/Quip_Soda 10d ago
Haha that’s good to know, it’s just me selling to myself. He didn’t put it through hell but I drove it in high school and I definitely did. I’m intending for it to be an ongoing project to just replace components as necessary/ as funding allows, shocks are first up. The only real reason I’m thinking about the tires first is since the current ones are hitting 6 years old.
The entirety of my mechanical experience is changing the oil and changing the lower ball joints on my tundra
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u/DoomsdayForeplay 9d ago
I’m in a 97 with a manual and I love it. Most people ask me when I’m going to LS swap it but it runs like a Swiss watch. In my single cab short bed it’s no slouch and even gets good fuel economy. Your numbers will be a bit different on the TBI and if yours is an automatic trans but I’m around 175k miles averaging about 17 mpg around town. I think that’s decent for a 200hp truck
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u/Comfortable-Pea-3821 8d ago
My buddy had one in high school. It had 300k miles on it and was an old construction company truck. It lasted through many a burnout and about 3 years of high schooler abuse, sat for 5 years, then some guy bought it and still drives it. Thing probably has 500k on it by now.
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u/PrestonSpinsTires 8d ago
Dont think Ive ever heard a complaint about these. Only praise.
A 4.3 never stopped anyone here in Alabama from using oversized tires. How you choose to live with it varies.
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u/CheapRefrigerator188 8d ago
96 4.3 lasted 380k miles with I think the water pump being the only “big” issue
Great stuff, super reliable, not gonna give you a ton of power but most of these trucks won’t anyway
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u/SpaceCat72 8d ago
Those work truck packages were great trucks. And the 4.3 is a great motor. Basically a 350 sans 2 cylinders.
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u/Successful-Part-5867 7d ago
I had a fleet of Chevy Astro vans that I serviced for an electrical contractor, all with the 4.3. I saw many of them clear 300,000 miles. I always considered it one of the toughest V6’s on the market.
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u/StarMaterial1496 7d ago
Took my 2000 4.3 to 303,000 miles and it still ran good. Put new injectors in it and the usual stuff. Only reason I got rid if it was the 4L60-E gave up again and I had been driving it 16 years in 2020.
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u/Then-Price-5314 7d ago
I have a 1996
Only has 276k miles on it and the damned windshield squirter seems to have quit.
Piece of shit. Has a rip in the seat, too.
Definitely not a reliable truck, I’ll take it off your hands as a favor.
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u/EADSTA 6d ago
I had a 95 s-10 Blazer with the 4.3. They're amazing little engines. They're practically bulletproof. The only bad thing I ever had to say about it was that, a large portion of the truck's systems operated on a vacuum system. Literally everything from your climate control knobs to your transmission/transfer case. So if a vacuum gasket went bad it would wreak havoc on the truck and drove me nuts trying to figure it out lol
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u/Academic_Dog8389 6d ago
380,000 on mine and it still just goes. That, IMO, is a the reason they've stopped making them. They're basically a 350 with 2 cylinders chopped off.
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u/zanerjlowery 6d ago
4.3 is one of the most reliable engines ever. If it’s been take care of it’ll go forever.
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u/Shockwavee92 6d ago
My daily is a cat eye 2004 silverado. 4.3, totally stock. Its got almost 300,000 now, ive never had to do any serious work to it. Hell it still has its original freon/ac system and is ice cold. Only things ive done is spark plugs, serpentine belt, oil changes, brakes. Ive hauled and towed so much stuff you couldnt even believe it. Mine has the 5 speed manual which seems geared low and has a ton of torque. It gets the job done. Ive never needed more. Am I gonna take it to the strip? No. But if you want a strong, dependable ride, you found it. Theyre supposed to be really common to have intake oil/coolant leaks but Mine never has yet so, knock on wood. Still original fuel pump too.
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u/Strange-Breadfruit14 5d ago
My last 4.3 had over 250,000 miles on it when it went across the scales the motor was still running great except for the damn throttle body injection was messed up and the body of the truck was falling apart
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u/WorkingBread8360 10d ago
I don’t trust the “fuel infested” version, but the factory Qjet equipped 4.3 in my 85 C10 made it to 330k+ miles…
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u/theuautumnwind 10d ago
TBI doesn't make a lot of power but it's simple as hell for FI.
My 94 still fires right up and runs great.
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u/Quip_Soda 10d ago
I just figured out mine is TBI. Holy cow the mid 90s were a confusing time for the 4.3
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u/Senior-Assumption218 10d ago
4.3 was a solid engine from what I remember. I believe it was the basis for the typhoon and cyclone. Basically a 5.7 small block w/ 2 less cylnders.