gibsonfarmsmo
Newbie
Hello,
I'm new to the forum but have been referencing from it for many years now. A little bit of background. I have two of these series of trucks. 98 2500 silverado, and 98 2500 sierra. Purchased used several years apart. I never intended to have two of the same trucks, but that is just how it worked out. Both possessing 5.7 vortecs, 5 speeds, and regular cabs. The difference being color (exterior and interior) and gear ratios (one 3:73, the other 4:10). I was in high school around the time the last of this series came out and was always a fan on them. I found them to be reliable, well built, and just an all around good work truck (because that is what a truck is used for, right?). I live in a rural farming area, and you see these trucks on the road more than any other make of this same genre (like 5 to 1...). The reason I stay with these trucks is very logical to me. I own them. No payments! In stock form, a newer truck with a 6.0 is hard to beat, but thrashed 10 year old truck around here still demands $12K. I figure I could put upwards of $5k into each truck and still be ahead of the game.
Anyway, here is where I am at. My job has pushed me into a different field (same job, just different "job"). This will require me to tug around a 8-10K load on a somewhat regular basis. That being the case, I need to delegate one of these trucks for this duty. My choice has been the 4:10 gmc. Its still pretty solid despite its 20 year age and 161,000 miles. I have decided, on a preventative plan, to pull the motor and go through it (rings, pistons, bearings, etc...). This change in work won't really pick up until after the first of the year, so I have plenty of time to do this. This truck will be my daily driver for the distant future so I really can't afford to have it go down on me. I'm no stranger to engine rebuilds so it's not the task or skill that I'm having trouble with, its cam selection.
when looking at cams, I know what all the numbers means, and I can decipher a dyno chart. In my case I'm looking for something with close to the same duration (@.050), but with some more lift. I'm retaining the original factory intake (with MPFI replaced over the spider injectors) and vortec heads. I'm aware of the limits factory lift springs, so I don't intend on going wild with lift. If over .475 I'll opt for the comp beehive, or the ls1 springs. I would love to go the route of the marine MPFI intake, but they appear to be made out of unobtainium.... A 0411 ecm will likely be added as well for tunability. Stock exhaust is fine with me. If anything a higher flow cat and a series 70 big block ii muffler. I don't like a "rumble" on a truck and I figure the engineers at GM kind of knew what they were doing.
commonly I have found that people have gone with the GM "395" cam that adds some duration and lift, but it falls off by 2 degrees at lsa (ecm friendly 111 stock to 109 "395"). here is where I'm struggling the most. This truck isn't a late 60 muscle car, nor to be found running down a 1/8 mile strip. Dyno charts and cam numbers seem to show engines running in the RPM range which just isn't practical for a daily driven work truck that weighs nearly 6K empty, especially pulling a load. I don't need nor want a lope of the engine at idle or at highway speed. I'm often times conducting business while driving and don't need the hum or rumble of the truck impeding the conversations.
I know there is a trade off from performance to stock, and I'm willing to accept some. I guess my question is, would I benefit from a slightly larger cam (likely to find something with similar duration with more lift), or would a set of 1.6 roller rocker achieve close to the same results (raising lift by about .030).
Any help would be appreciated. Sorry for writing a book here.....
I'm new to the forum but have been referencing from it for many years now. A little bit of background. I have two of these series of trucks. 98 2500 silverado, and 98 2500 sierra. Purchased used several years apart. I never intended to have two of the same trucks, but that is just how it worked out. Both possessing 5.7 vortecs, 5 speeds, and regular cabs. The difference being color (exterior and interior) and gear ratios (one 3:73, the other 4:10). I was in high school around the time the last of this series came out and was always a fan on them. I found them to be reliable, well built, and just an all around good work truck (because that is what a truck is used for, right?). I live in a rural farming area, and you see these trucks on the road more than any other make of this same genre (like 5 to 1...). The reason I stay with these trucks is very logical to me. I own them. No payments! In stock form, a newer truck with a 6.0 is hard to beat, but thrashed 10 year old truck around here still demands $12K. I figure I could put upwards of $5k into each truck and still be ahead of the game.
Anyway, here is where I am at. My job has pushed me into a different field (same job, just different "job"). This will require me to tug around a 8-10K load on a somewhat regular basis. That being the case, I need to delegate one of these trucks for this duty. My choice has been the 4:10 gmc. Its still pretty solid despite its 20 year age and 161,000 miles. I have decided, on a preventative plan, to pull the motor and go through it (rings, pistons, bearings, etc...). This change in work won't really pick up until after the first of the year, so I have plenty of time to do this. This truck will be my daily driver for the distant future so I really can't afford to have it go down on me. I'm no stranger to engine rebuilds so it's not the task or skill that I'm having trouble with, its cam selection.
when looking at cams, I know what all the numbers means, and I can decipher a dyno chart. In my case I'm looking for something with close to the same duration (@.050), but with some more lift. I'm retaining the original factory intake (with MPFI replaced over the spider injectors) and vortec heads. I'm aware of the limits factory lift springs, so I don't intend on going wild with lift. If over .475 I'll opt for the comp beehive, or the ls1 springs. I would love to go the route of the marine MPFI intake, but they appear to be made out of unobtainium.... A 0411 ecm will likely be added as well for tunability. Stock exhaust is fine with me. If anything a higher flow cat and a series 70 big block ii muffler. I don't like a "rumble" on a truck and I figure the engineers at GM kind of knew what they were doing.
commonly I have found that people have gone with the GM "395" cam that adds some duration and lift, but it falls off by 2 degrees at lsa (ecm friendly 111 stock to 109 "395"). here is where I'm struggling the most. This truck isn't a late 60 muscle car, nor to be found running down a 1/8 mile strip. Dyno charts and cam numbers seem to show engines running in the RPM range which just isn't practical for a daily driven work truck that weighs nearly 6K empty, especially pulling a load. I don't need nor want a lope of the engine at idle or at highway speed. I'm often times conducting business while driving and don't need the hum or rumble of the truck impeding the conversations.
I know there is a trade off from performance to stock, and I'm willing to accept some. I guess my question is, would I benefit from a slightly larger cam (likely to find something with similar duration with more lift), or would a set of 1.6 roller rocker achieve close to the same results (raising lift by about .030).
Any help would be appreciated. Sorry for writing a book here.....
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