7.4 info request

1-8-4-3-6-5-7-2 said:

Who does good tunes nowadays? Are mail order tunes where I send in the computer and get it back still a thing?

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df2x4 said:

Yes, Black Bear Performance is still doing mail order tunes for '96+ PCMs and they're great people to work with.

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1-8-4-3-6-5-7-2 said:

Who does good tunes nowadays? Are mail order tunes where I send in the computer and get it back still a thing?

Years ago on my '96 Suburban the exhaust pipe kept cracking near where it bolts to the passenger side manifold. The guy in the exhaust shop said it was because the A/C drain dripped on it. Instead of replacing it with the pipe with cats in it I went with this instead https://www.jegs.com/i/JEGS/555/310...MInqvu18X_5wIVEMZkCh1Z1QjeEAQYASABEgKF0vD_BwE and got a Black Bear tune IIRC. I didn't go wild with the tune, but did have the rear O2 sensors turned off, top speed limiter removed, speedometer corrected, and possibly shift points altered.

Otherwise yeah, I'd love to go look at the dually for sale. The problem is that it's a 2 hour drive 1 way to see it and I've called the dealer 3 times with no answer, left a message asking them to return my call, and sent them an email 4 days ago that remains unanswered as well. I'm not about to make a 4 hour trip to go see a truck that may have been sold already or is a hunk of junk or the dealer is closed for the day, which brings me to my next question below...

Please provide your honest opinion of this truck based on the info and pics in the ad https://www.carsforsale.com/used-ca...decatur-il-d367361/inventory/details/62952469

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88monteSS said:

I have a black bear tune on my 97 454, I asked about octane and he said that there was no benefit from going to a higher octane on the 454s.

Mine is at 268k with no major issues other than an occasional puff of oil on startup. Average mpg is usually around 12-13 whether I'm ripping on it or not, but it's gone up to closer to 14 after I replaced the rear hub bearings. Towing it usually stays around 9.


Here's what I would suggest if you get a 96+ 454:

1. Upgrade the injectors - besides being notorious for leaking, the stock ones are 19# and barely adequate for the rated hp. At the least I would replace the injectors with the ones from 5-0 if they haven't been done already. Better yet would be to go to a slightly bigger size. There used to be a chart that showed which injectors were plug & pay, along with if they needed a tune adjustment. I'll have to search the way back machine to see if I can find a copy of it.

2. While you're doing the injectors, go ahead and do the lower intake gaskets since you'll be most of the way there. Fortunately the big blocks tend to leak externally rather than internally like the vortec small blocks. This will also give you the chance to inspect the distributor gear.

3. 0411 pcm swap. Newer & better PCM that has more tuning support. If you get an auto this will give you tow/haul mode like the newer trucks. Lextech has a conversion spreadsheet that makes it very easy, if he's not active on any forums these days I can give you his email to get it.

3.5. Tune

4. 180 thermostat. Gives you a little bit of a buffer before you start overheating if you're working it hard. That said, with the 180 tstat the only time mine has ever gone over 195 is when the tstat was going bad.

5. Oil cooler lines. They're notorious for leaking. Most convert them to use braided lines or delete them. I replaced mine once with new acdelco lines & they lasted a year before the new ones started seeping. Rather than make replacing them a regular thing I replaced them with hydraulic hoses.

Sent from my XT1254 using Tapatalk

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stutaeng said:

Yes, but the 4.3 Vortec, along with the 5.7 Vortec has the infamous "spider injectors." They are under the intake plenum. My DD is a '99 Silverado NBS ECSB with 256k miles. It has developed an intermittent miss and I suspect it may be the injectors. They are the original. I'm not complaining with so many miles on it. I did the intake manifold gasket leak replacement just last year, but didn't mess with the upper plenum. Just haven't had time to diagnose it.

The outboard injectors like the 7.4, 8.1 and Gen III LS+ are much a much better design.

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88monteSS said:

I have a black bear tune on my 97 454, I asked about octane and he said that there was no benefit from going to a higher octane on the 454s.

Mine is at 268k with no major issues other than an occasional puff of oil on startup. Average mpg is usually around 12-13 whether I'm ripping on it or not, but it's gone up to closer to 14 after I replaced the rear hub bearings. Towing it usually stays around 9.


Here's what I would suggest if you get a 96+ 454:

1. Upgrade the injectors - besides being notorious for leaking, the stock ones are 19# and barely adequate for the rated hp. At the least I would replace the injectors with the ones from 5-0 if they haven't been done already. Better yet would be to go to a slightly bigger size. There used to be a chart that showed which injectors were plug & pay, along with if they needed a tune adjustment. I'll have to search the way back machine to see if I can find a copy of it.

2. While you're doing the injectors, go ahead and do the lower intake gaskets since you'll be most of the way there. Fortunately the big blocks tend to leak externally rather than internally like the vortec small blocks. This will also give you the chance to inspect the distributor gear.

3. 0411 pcm swap. Newer & better PCM that has more tuning support. If you get an auto this will give you tow/haul mode like the newer trucks. Lextech has a conversion spreadsheet that makes it very easy, if he's not active on any forums these days I can give you his email to get it.

3.5. Tune

4. 180 thermostat. Gives you a little bit of a buffer before you start overheating if you're working it hard. That said, with the 180 tstat the only time mine has ever gone over 195 is when the tstat was going bad.

5. Oil cooler lines. They're notorious for leaking. Most convert them to use braided lines or delete them. I replaced mine once with new acdelco lines & they lasted a year before the new ones started seeping. Rather than make replacing them a regular thing I replaced them with hydraulic hoses.

Sent from my XT1254 using Tapatalk

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Christian Steffen said:

Options are more limited for 96-97 trucks, black bear is probably the best mail order tuner from what i hear, I haven't personally used him though. Personally i would have him do a 91 octane tune, delete TM, change shift points etc.

As far as the truck goes, a rust free C3500 for $3500? Hell that seems like a good deal.

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1-8-4-3-6-5-7-2 said:

Please provide your honest opinion of this truck based on the info and pics in the ad https://www.carsforsale.com/used-ca...decatur-il-d367361/inventory/details/62952469

Click to expand...