Gen 6 454 Questions

[Road Trip]

Read through it, pointed to some other great articles, my only concern most of these 8.1 swap include quite a bit of fabrication or custom work, which I’m not apposed to, but I’d like to keep it as oem as possible. If I could just find a vin to order the 01-02 3500HD “classic” oem harnesses, computers, and related accessories, I’ve found loads of complete 8.1’s near me for about the same price as a good GenVI short block. But I work at a GM dealership so maybe I could talk to some of the parts guys and see what they can work up on the computers.

00CrewCab,

I happen to own a recently acquired '99 C2500 with the L29, and although the engine has racked up 220K miles it still runs well.

Even so, I've been thinking about what to do if the engine were to wear out? My first thought was to use this as an excuse to
upgrade to a Gen 7 8.1 (all treasure yard sourced) ...but the more I looked into the cost of even just refreshing said
8.1 prior to stuffing gave me pause. Unfortunately, it is just different enough that there isn't much aftermarket support.

Also, I've done enough engine swaps that I realize that's it all the conversion details that become the tail that wags the project dog.

Try as I might, what seems to promise me the most grins per Benjamin spent is one of the following categories:

1) Refresh existing engine in stock tune. Think stock spec blueprint. *Minor* head porting, optimum quench, upgrade to 0411, better exhaust, sharp tune, enjoy.
(sharp chore truck with stock manners, still ~290hp/410+ ft/lbs of torque, could be driven by anyone.)

2) Same as #1, upgrade cam to what GM should have installed to maximize what the torque-oriented intake can make. Add a correctly-sized turbo
to pick up where the stock intake starts to taper off, and use this boost to produce a sparkling top end charge. (HP = Torque. Torque = 450+?)

3) Same as #2, but install the 496ci rotating assembly. (Better manners down low, more torque throughout, making a good thing just that much better.)

4) Same as #3, but now take advantage of all the backwards-compatible Mk IV performance goodies. (Think what would Lingenfelter do?)

Lingenfelter/Mercury Marine 605ci Big Block -- '94 GMC Yukon "Concept Car" 0-60 in 4.6 seconds, naturally aspirated

You must be registered for see images attach

I like the juxtaposition of this HO motor in an otherwise stock-appearing 1994 power barn. Suburban upgrade, anyone? Subdivision?

****

Realistically, I can justify step #1 as maximizing what I have for the least money spent. Roll the calendar back to when it rolled off the
Arlington, TX assembly line in the summer of '99. While I'm at it, I'll refresh the 4L80-E, checking another box on my personal Bucket List.
The truck will certainly outlast yours truly, but that's a good thing.

...and if I haven't run out of project steam by then, I would then absolutely add Step #2, even though I don't need it, and certainly
can't justify it. What can I say? Sleepers are my favorite vehicles of all, they fit my sense of humor. (Chore Truck)

And steps #3, #4, or Lingenfelter+? It will never happen...but it's fun to think about while sitting in the waiting room
at the VA hospital. Everyone else is so serious. Me so happy! :0)

****

Let us know what you decide to do. And if the 8.1 upgrade is your Holy Grail, I'll be watching
intently. I'm here to watch & learn, and that would be a great adventure.

Enjoy your GMT400 journey --

 

[00CrewCab]

00CrewCab,

I happen to own a recently acquired '99 C2500 with the L29, and although the engine has racked up 220K miles it still runs well.

Even so, I've been thinking about what to do if the engine were to wear out? My first thought was to use this as an excuse to
upgrade to a Gen 7 8.1 (all treasure yard sourced) ...but the more I looked into the cost of even just refreshing said
8.1 prior to stuffing gave me pause. Unfortunately, it is just different enough that there isn't much aftermarket support.

Also, I've done enough engine swaps that I realize that's it all the details that become the tail that wags the project dog.

Try as I might, what seems to give me the most grins per benjamin spent is one of the following categories:

1) Refresh existing engine in stock tune. Think stock spec blueprint. *Minor* head porting, optimum quench, upgrade to 0411, better exhaust, sharp tune, enjoy.
(sharp chore truck with stock manners, still ~290hp/410+ ft/lbs of torque, could be driven by anyone.)

2) Same as #1, upgrade cam to what GM should have installed to maximize what the torque-oriented intake can make. Add a correctly-sized turbo
to pick up where the stock intake starts to taper off, and use this boost to produce a sparkling top end charge. (HP = Torque. Torque = 450+?)

3) Same as #2, but install the 496ci rotating assembly. (Better manners down low, more torque throughout, making a good thing just that much better.)

4) Same as #3, but now take advantage of all the backwards-compatible Mk IV performance goodies. (Think what would Lingenfelter do?)

Lingenfelter 605ci Big Block -- '94 GMC "Concept Car" 0-60 in 4.6 seconds, naturally aspirated

You must be registered for see images attach

Note: I like the juxtaposition of this HO motor in an otherwise stock-appearing power barn.

****

Realistically, I can justify step #1 as maximizing what I have for the least money spent. Roll the calendar back to when it rolled off the
Arlington, TX assembly line in the summer of '99. While I'm at it, I'll refresh the 4L80-E, checking another box on my Bucket List.
The truck will certainly outlast yours truly, but that's a good thing.

...and if I haven't run out of project steam by then, I would then absolutely add Step #2, even though I don't need it, and certainly
can't justify it. What can I say? Sleepers are my favorite vehicles of all, they fit my sense of humor. (Chore Truck)

And steps #3, #4, or Lingenfelter+? It will never happen...but it's fun to think about while sitting in the waiting room
at the VA hospital. :0)

****

Let us know what you decide to do. And if the 8.1 upgrade is your Holy Grail, I'll be watching
intently. I'm here to watch & learn, and that would be a great adventure.

Enjoy your GMT400 journey --

In the past couple years I’ve noticed an uptick in 8.1 aftermarket support. Which I don’t plan on any heavy modification for the 8.1 for this build. A mild build with maybe a “bolt on” supercharger. Keep a very mild cam, it’s going to be a towing rig for me. High HP isn’t as important as high TQ numbers. And eventually I plan to figure out how to do a manual trans swap and keep my electric transfer case. But that’s way in the future when I’ve got more time and money for it to sit for presumably months on end digging through wiring and computer issues. My end goal for this truck is “bubba”/sleeper build. I want the “average Joe” to look at it and think it’s just some well maintained 90’s truck, but take a second look and it’ll be truly one of a kind. Full black leather interior with purple double stitching, all oem wood trim but stained a dark purple, with newer technology sprinkled throughout, gmt800 sunroof, tundra rear window, custom heated and cooled seats, double din radio with full “hidden” sound system. Coil spring solid front axle swap, 8.1 supercharged with manual trans (prob a ZF6), electric transfer case, widened rear end (heard 03+ van axle is the right one), disk brakes, 3500 springs, air bags, front locker with limited slip rear end. But the exterior will look pretty “normal”. Ram flake metallic black, chrome grille with clear headlights, clear tails and third light. Chrome factory bumpers with maybe a ranch hand style bolt on grille guard, gmt800 16” wheels, and at or mt tires. I’ve got a whole list for the build, including every small detail I can think of. But the main goal right now is to get the truck back on the road, seeming my blazer isn’t technically legal to drive right now and local PD has been on me about it. I’ll probably create a whole new thread when I go to do this build, which the start to is hopefully about a year away (except the stock 8.1 swap). Once I can get some parts figured out, I’ll keep this thread updated with the swap, did a quick estimate on the “factory” 8.1 swap vs finding a good Gen6 (in my area) and for roughly $1k more (using mostly salvage yard parts) I can get the 8.1 swap done.

 

[Road Trip]

In the past couple years I’ve noticed an uptick in 8.1 aftermarket support. Which I don’t plan on any heavy modification for the 8.1 for this build. A mild build with maybe a “bolt on” supercharger. Keep a very mild cam, it’s going to be a towing rig for me. High HP isn’t as important as high TQ numbers. And eventually I plan to figure out how to do a manual trans swap and keep my electric transfer case. But that’s way in the future when I’ve got more time and money for it to sit for presumably months on end digging through wiring and computer issues. My end goal for this truck is “bubba”/sleeper build. I want the “average Joe” to look at it and think it’s just some well maintained 90’s truck, but take a second look and it’ll be truly one of a kind. Full black leather interior with purple double stitching, all oem wood trim but stained a dark purple, with newer technology sprinkled throughout, gmt800 sunroof, tundra rear window, custom heated and cooled seats, double din radio with full “hidden” sound system. Coil spring solid front axle swap, 8.1 supercharged with manual trans (prob a ZF6), electric transfer case, widened rear end (heard 03+ van axle is the right one), disk brakes, 3500 springs, air bags, front locker with limited slip rear end. But the exterior will look pretty “normal”. Ram flake metallic black, chrome grille with clear headlights, clear tails and third light. Chrome factory bumpers with maybe a ranch hand style bolt on grille guard, gmt800 16” wheels, and at or mt tires. I’ve got a whole list for the build, including every small detail I can think of. But the main goal right now is to get the truck back on the road, seeming my blazer isn’t technically legal to drive right now and local PD has been on me about it. I’ll probably create a whole new thread when I go to do this build, which the start to is hopefully about a year away (except the stock 8.1 swap). Once I can get some parts figured out, I’ll keep this thread updated with the swap, did a quick estimate on the “factory” 8.1 swap vs finding a good Gen6 (in my area) and for roughly $1k more (using mostly salvage yard parts) I can get the 8.1 swap done.

Nice! I absolutely get what you are contemplating/planning. Built, not bought. (!)

And please do start a build thread. I originally found & used this site strictly for
broke/fix info, but reading other people's build/rebuild threads has become one of
my favorite things about this forum. There are some super talented/motivated
folks in here, and I enjoy studying their handiwork.

And Welcome to the GMT400 forum. Lot's of super people in here who share a deep
appreciation for what these machines bring to the table.

Happy hunting for all the perfect bits --