454 TBI vs 454 Vortec OR 350 vortec?

[JCribb]

Is your current truck a 5 speed, and is it the light duty 5 speed? If so then the crew cab 3500 with 5 speed is gonna be the NV4500 and it's a very different driving experience. Essentially you're driving a 4 speed with overdrive, because the low 1st gear is rarely used unless you're trying to get a heavy load off the line. It shifts "heavy" despite the softening up of the carbon-fiber syncros, if they're still in there and haven't been destroyed by someone using the wrong lube, since the correct stuff is $20+ a quart.

For fun factor *combined with* reliability, I'd go with the TBI 454. The Vortec 454 will kick it's ass but then you have the occasional expensive battle with the injectors (don't forget the regulator and be careful with the somewhat fragile fuel rail), and the POS plastic distributor that the cap tabs break off and the bushing up top wears out. The Vortec EGR tube setup sucks. Also, Vortecs of big or small block variety will require you to have a scan tool good enough to read the cam retard angle in order to set them up properly once you replace that junk distributor. Can't do it with a timing light.

Richard

I used to have the light duty pos 5 speed until I broke all three of them, that is the original and the two replacements. I have more torque than the factory designed so I broke stuff. I have had the nv4500 in my truck for almost 3 years now, so I know all about the heavy semi truck feeling shifting it does. I think I’ve used 1st gear a handful of times. Thanks for the feedback.

 

[454cid]

I have almost 300K miles on my Vortec 454. It does use a lot of gas. I've had issues with my intake manifold gasket. It was replaced once, but the person doing it didn't use Loctite on the bolts as GM specs so a bolt in the same spot as the previous leak started backing out. The good thing is that the 454 leaks to the outside, not into the oil like the 350 seems to do. The 454 also doesn't have the goofy spider injection system. It uses regular injectors. The OEM injectors are supposedly a bad design, and I thought I needed new injectors for a long time. It turns out my hard starting issue was more of a weak fuel pump. The pump finally quit and when I replaced it, along with the new design harness, the hard starting went away by about 95%. A new starter, when the original was having problems, fixed the other 5%. I've replaced the cap and rotor twice, I think. My truck is an automatic. I've never driven the NV4500.

 

[Sparkysikes]

Ok 6.5 motor but I ran her heavy every day and towed occasionally. Going up a steep grade like seriously almost 45* I couldn't come out of 2nd into 3rd as the gear ratio was too spread out. And I had similar issues while towing but pretty much just on grades.

I swapped out to automatic as I had too many issues (come to find out bad clutch pedal caused the death of many a slave/master cyl) but same grades same towing and the truck flew up no issues part throttle.

My buddy has a 95 ram cummins and manual to manual he would walk me. With the auto and 100hp less he couldn't catch me til we were both on OD.

This might be the auto keeps the boost better on the diesels. Or not as gm3 spool crazy quick. I do miss shifting while not stuck in traffic but I the 4l80e works better for me. The mpg difference is about 1.5 per gallon less with auto