Which Is More Reliable... The 350 Or The 454?

green 788 · April 30, 2009

I seem to see more big blocks needing work early, as opposed the the small blocks.

My boss has a 454 in his ton dually GMC, and with about 100K on it, it's needing intake manifold gaskets (but this could be from red anti-freeze, I don't know)...

Of course the 454's are usually installed in HD trucks, and are of course worked harder than the 350's are, so that could contribute to more maintenance on the 454's.

I have a 1996 GMC K3500, crew cab and it's got a small block in it. I wish (at least I think I wish) that it had a big block, due to the power factor. But this truck got a new crate engine from a GMC dealer about a year ago (before I owned the truck), with 165,000 on the original 350. The original motor had gone bad due to a failed water pump and the construction worker just kept driving the truck and killed the engine--otherwise it may have gone to 200K, who knows?

Is there any consensus as to which of these two engines (the 350 or the 454) is the most dependable for long term use? I have around 45,000 on the new 5.7 in my truck now, and hope it'll go at least another 100K...

Dan

Draenor · April 30, 2009

I have seen both as reliable engines. It is true that the 454 being used in HD applications could be more susceptible(sp) to problems. Both are good engines, its all in how you take care of them.

66nova · April 30, 2009

I seem to see more big blocks needing work early, as opposed the the small blocks.

My boss has a 454 in his ton dually GMC, and with about 100K on it, it's needing intake manifold gaskets (but this could be from red anti-freeze, I don't know)...

Of course the 454's are usually installed in HD trucks, and are of course worked harder than the 350's are, so that could contribute to more maintenance on the 454's.

I have a 1996 GMC K3500, crew cab and it's got a small block in it. I wish (at least I think I wish) that it had a big block, due to the power factor. But this truck got a new crate engine from a GMC dealer about a year ago (before I owned the truck), with 165,000 on the original 350. The original motor had gone bad due to a failed water pump and the construction worker just kept driving the truck and killed the engine--otherwise it may have gone to 200K, who knows?

Is there any consensus as to which of these two engines (the 350 or the 454) is the most dependable for long term use? I have around 45,000 on the new 5.7 in my truck now, and hope it'll go at least another 100K...

Dan

I think both are very reliable engines WHEN they are taken care of correctly. But if I am picking one chevy engine that I think about for reliability, I don't think you can beat a good old 350. That engine can take a lickin and keep on tickin.

I currently have 175,000 miles on my 350 in my 95 and it still runs strong.

rodram · April 30, 2009

Maintenance is the key to longevity of either of these Chevy engines. The 454 (7.4L) will give you more power if you really need it for hauling weight or towing all the time... but if your vehicle is a daily driver (like mine and most others...) and you haul something only once in a while, then the 350 (5.7L) will serve you well. The 454 will be tougher on fuel consumption and cost you more in daily operating expense. Intake manifold gaskets are an inevitable weakness in either of these engines and you are going to have to replace at least one if you drive them for several years (... just don't use the GM gasket when you do the replacement). If you are looking at a 1996 - 2000, then the fuel injection systems are different between the 5.7L and the 7.4L with the 5.7L and other smaller small blocks having the Sequential Central Fuel Injection with the problematic (sticking) poppet valves. But you can replace these with the Multiport Flexible Injection system conversion that the 7.4L engine uses.

I have 208K km (130K miles) on my 97 and plan to keep it running for many years yet.

VR021302 · April 30, 2009

I had almost 300k on my 94 350 and it was still going strong 5 yrs after I sold it.

pennzoil29 · May 1, 2009

I've put well over 200K on many a 350. The truck I have now has a 177+k on her, and will definately go well over 200K. You just have to keep the oil changed, and never, ever let them over heat, and they'll run forever.

kuhl_530 · May 1, 2009

+1 I have 210k on my 95 350, but the 95 came with the throttle body injection, not the vortec engine. I've heard that the throttle body trucks had fewer fuel problems than the early vortecs. Reguardless, the 350 is still a terrific engine, I'm just very sad to see them go away . I am doing an intake manifold replacement in the near future, but for 200+k, I could be much worse off!

L29er · May 1, 2009

Maintenance is the key to longevity of either of these Chevy engines. The 454 (7.4L) will give you more power if you really need it for hauling weight or towing all the time... but if your vehicle is a daily driver (like mine and most others...) and you haul something only once in a while, then the 350 (5.7L) will serve you well. The 454 will be tougher on fuel consumption and cost you more in daily operating expense. Intake manifold gaskets are an inevitable weakness in either of these engines and you are going to have to replace at least one if you drive them for several years (... just don't use the GM gasket when you do the replacement). If you are looking at a 1996 - 2000, then the fuel injection systems are different between the 5.7L and the 7.4L with the 5.7L and other smaller small blocks having the Sequential Central Fuel Injection with the problematic (sticking) poppet valves. But you can replace these with the Multiport Flexible Injection system conversion that the 7.4L engine uses.

+1, what he said.

Keep the lube fresh and keep her cool! She`ll last a long time!

carneyman · May 1, 2009

Well, we use both 350's and 454's on the farm, doing the same thing. It seems we have to do more on the 454's as far as gaskets are concerned, but the 350's are more likely to throw a rod or have a piston burn up or we have to replace the camshaft. Granted, this is after running them 24/7/210 a year for a couple of years. So, IMO, they are both pretty reliable. You should get a few hundred thousand miles out of it if you take care of it.

RaGeFeAr · May 11, 2009

My 91 went thru 3 transmissions, a fuel pump, countless starters and alternators, had over 200K on it when I sold it and ran like a champ. I miss her and I wish I still had her over my 07. You can just tell that this truck isn't going to last me anywhere near as long as the 91 did.

NFSGamerUSA · May 12, 2009

My boss has a 454 in his ton dually GMC, and with about 100K on it, it's needing intake manifold gaskets (but this could be from red anti-freeze, I don't know)...

That's a common trait of all Vortec Generation I small blocks. Fel-Pro's got a nice kit to fix that for a good, long time, though.

Reliability should be identical provided they're used and maintained the same way. In reality, though, 454's usually face more work if they're in trucks. Then again, they probably face more work in cars, too, if they're driven for their intended purpose. On the other hand, a 454 will spend more time in the lower RPM range than a 350, so that's less wear on the rings, pistons, cylinder walls, etc. That brings me back to saying they should be identical and that it's a toss-up. There are no design cons in one that aren't found in the other, so it really comes down to how they're used.