97 454 L29 Vortec into a 80 K25

[TubeTruck]

http://www.gmtruckcentral.com/articles/24x.html

This has some useful information for you. I read through this several times before I started cutting wires

Sweet, thanks

 

[Bextreme04]

http://www.gmtruckcentral.com/articles/24x.html

This has some useful information for you. I read through this several times before I started cutting wires

That thread says that he needed to convert the crank sensor to the L21 sensor for the 24x, but I don't think tha is the case with the EFI Connection reluctor. The L21 reluctor is dual sided, which is why the sensor is different. The EFI connection reluctor is not dual sided, so I think it will work with the stock L29 sensor.

The rest of the information in there seems really great, thanks for posting it!

 

[Markmx6]

That thread says that he needed to convert the crank sensor to the L21 sensor for the 24x, but I don't think tha is the case with the EFI Connection reluctor. The L21 reluctor is dual sided, which is why the sensor is different. The EFI connection reluctor is not dual sided, so I think it will work with the stock L29 sensor.

The rest of the information in there seems really great, thanks for posting it!

I was pretty sure that the reason EFI Connection had difficulty having the reluctor wheels manufactured was that they are in fact dual sided like the L21, it just doesn't look like it in the pictures.

Here is another site to look at before you start cutting, if I remember correctly this guy had the prototype reluctor wheel that EFI connection makes. I am almost positive you will need to convert the sensor too. You can find the sensor cheaper than EFI connection sells it for though.

Never mind, I forgot you already bought the reluctor wheel and would know better than I do..

 

[Bextreme04]

I was pretty sure that the reason EFI Connection had difficulty having the reluctor wheels manufactured was that they are in fact dual sided like the L21, it just doesn't look like it in the pictures.

Here is another site to look at before you start cutting, if I remember correctly this guy had the prototype reluctor wheel that EFI connection makes. I am almost positive you will need to convert the sensor too. You can find the sensor cheaper than EFI connection sells it for though.

Never mind, I forgot you already bought the reluctor wheel and would know better than I do..

I have it, it is not dual sided. I just went back to the EFI connection website and looked it up and it specifically states that the 4" 24x reluctor is designed to use all of the stock L29 components including crank sensor. They actually also sell a dual sided version for a crazy $80 more that is a direct replacement for the L21 reluctor and requires the L21 crank sensor.

The crazy thig is that it would actually be cheaper to buy the L29 24x reluctor AND the L29 crank sensor tan to buy a replacement L21 reluctor from them. Which is especially crazy when you consider that up until a few years ago, you could buy an L21 reluctor from GM for under $20.

 

[TubeTruck]

I'm learning here. What reluctor wheel does the L29 have? I've heard of 24x and 58x and see you guys taking about putting a 24x on the L29 for the CNP. Does the L21 use CNP? Is that why you need an L21 reluctor? Or am I getting confused here? Lol

 

[Bextreme04]

I'm learning here. What reluctor wheel does the L29 have? I've heard of 24x and 58x and see you guys taking about putting a 24x on the L29 for the CNP. Does the L21 use CNP? Is that why you need an L21 reluctor? Or am I getting confused here? Lol

Lol. It can get confusing quick. The L29 originally comes with the same ignition system as the L31 5.7L Vortec. That is a Vortec distributor with a 1x cam sensor and a 4” 4x Crank reluctor. The L29 is the 454 that was optional in 96-99 2500 Suburbans and Silverado’s. The L21 is an almost identical 454 that had forged internals, an identical Vortec distributor with 1x cam sensor but NO distributor cap and rotor(it had a plastic flat cap instead), a 24x crank reluctor and dual sided sensor, and LS style CNP ignition. The L21 was an optional engine on Kodiac medium duty trucks in 99-00 and also some other odd applications. If you see a BBC with LS coil packs attached to molded studs on the valve covers, it’s either an L21 or an 8.1L Vortec. The LS’s used mounting brackets, but the BBC factory CNP setups actually had the coil mounting brackets cast into the valve covers.

 

[TubeTruck]

Lol. It can get confusing quick. The L29 originally comes with the same ignition system as the L31 5.7L Vortec. That is a Vortec distributor with a 1x cam sensor and a 4” 4x Crank reluctor. The L29 is the 454 that was optional in 96-99 2500 Suburbans and Silverado’s. The L21 is an almost identical 454 that had forged internals, an identical Vortec distributor with 1x cam sensor but NO distributor cap and rotor(it had a plastic flat cap instead), a 24x crank reluctor and dual sided sensor, and LS style CNP ignition. The L21 was an optional engine on Kodiac medium duty trucks in 99-00 and also some other odd applications. If you see a BBC with LS coil packs attached to molded studs on the valve covers, it’s either an L21 or an 8.1L Vortec. The LS’s used mounting brackets, but the BBC factory CNP setups actually had the coil mounting brackets cast into the valve covers.

Thanks for clearing that up. I knew about some of the basics like the L21 having forged internals but was lost when it came to reluctors and what they were for. I'm thinking it's like a magnetic pickup that fires off the coils so that helps me.

I think I'm going to rebuild this as stock for now until I learn more. I'll upgrade over time. I need to learn about moving segments and stuff over to my 0411 as well so it's going to be too steep a learning curve to keep my daily running for now. I'll definitely stay involved and watch your progress though.

 

[TubeTruck]

I've been picking at the harness, all the loom and tape just crumbled so it was kind of easy to unravel. Seems the mechanic that took the motor apart broke all the injector connectors. I had to buy all those and am in process of making my own harness. I've also cut all the wires for the emissions and working on making the transmission harness a separate one. I'm going to put 2 connectors near the firewall so all I have to do is plug it in when I get around to putting the 4L80e in.

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I'm also making a list of things I need to upgrade before I drop this thing in. I bought some relays and doing the headlight "upgrade" so the rest of the wiring harness doesn't see a voltage drop. A dual battery setup is in the works as well. I bought an EFI 40 gal fuel tank (the one with the tray) a while ago and planned on using the 80's EFI sending unit and hanging the pump for the 454 on it but am going a different route. Spoke with a friend who parts out vehicles and he has a couple late model gas tanks sitting around. He's going to cut the sending unit mount out of one of the tanks and send it to me. I'm going to weld it into my new tank so I can use the bucket style sending unit, then run a high pressure fuel line up the driver's side frame rail.

I'm also going to make a tuning harness so I can tune the 0411 before putting it into the truck. With regards to moving segments over to run the distributor, I'll have to figure out how to reverse that later down the road when I swap to a CNP setup.

 

[Bextreme04]

I've been picking at the harness, all the loom and tape just crumbled so it was kind of easy to unravel. Seems the mechanic that took the motor apart broke all the injector connectors. I had to buy all those and am in process of making my own harness. I've also cut all the wires for the emissions and working on making the transmission harness a separate one. I'm going to put 2 connectors near the firewall so all I have to do is plug it in when I get around to putting the 4L80e in.

You must be registered for see images attach

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I'm also making a list of things I need to upgrade before I drop this thing in. I bought some relays and doing the headlight "upgrade" so the rest of the wiring harness doesn't see a voltage drop. A dual battery setup is in the works as well. I bought an EFI 40 gal fuel tank (the one with the tray) a while ago and planned on using the 80's EFI sending unit and hanging the pump for the 454 on it but am going a different route. Spoke with a friend who parts out vehicles and he has a couple late model gas tanks sitting around. He's going to cut the sending unit mount out of one of the tanks and send it to me. I'm going to weld it into my new tank so I can use the bucket style sending unit, then run a high pressure fuel line up the driver's side frame rail.

I'm also going to make a tuning harness so I can tune the 0411 before putting it into the truck. With regards to moving segments over to run the distributor, I'll have to figure out how to reverse that later down the road when I swap to a CNP setup.

That’s about what mine looked like too. I got a painless 24 pin firewall bulkhead connector to pass through new wiring into the cab. I’m also planning on a connector to disconnect the trans/tcase harness.

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I ended up getting a TBI blazer 30 gal tank for mine. The suburban donor truck had a 42 Gal and the sender/pump assembly from the donor fits right into the 30 gallon from the blazer except the fill and outlets are clocked 180 degrees off from where they should be. I haven’t decided whether I’m going to try and rotate the lock ring or if I’ll just modify a TBI sender with my 97 EFI pump.

keep in mind it’s more than a segment swap when you go CNP. You’ll have to replace the crank tone wheel under the timing cover and re-pin the injector order to account for the LS firing order being different. You’ll also have to run a whole new ignition harness and remove the old ignition stuff that ran behind the intake. I’d suggest provisioning and labeling the necessary wiring now while the harness is out and there, before it’s all freshly wrapped. You should only need to swap two sets of wires for the injectors and you can have the ignition harness run all the way to the coil pack harness plugs at the valve covers and even pinned into the 0411 so it’s just a Clío in and go situation. EFI connection sells the right connectors and pins for pretty cheap.

 

[Markmx6]

I've been picking at the harness, all the loom and tape just crumbled so it was kind of easy to unravel. Seems the mechanic that took the motor apart broke all the injector connectors. I had to buy all those and am in process of making my own harness. I've also cut all the wires for the emissions and working on making the transmission harness a separate one. I'm going to put 2 connectors near the firewall so all I have to do is plug it in when I get around to putting the 4L80e in.

You must be registered for see images attach

You must be registered for see images attach

I'm also making a list of things I need to upgrade before I drop this thing in. I bought some relays and doing the headlight "upgrade" so the rest of the wiring harness doesn't see a voltage drop. A dual battery setup is in the works as well. I bought an EFI 40 gal fuel tank (the one with the tray) a while ago and planned on using the 80's EFI sending unit and hanging the pump for the 454 on it but am going a different route. Spoke with a friend who parts out vehicles and he has a couple late model gas tanks sitting around. He's going to cut the sending unit mount out of one of the tanks and send it to me. I'm going to weld it into my new tank so I can use the bucket style sending unit, then run a high pressure fuel line up the driver's side frame rail.

I'm also going to make a tuning harness so I can tune the 0411 before putting it into the truck. With regards to moving segments over to run the distributor, I'll have to figure out how to reverse that later down the road when I swap to a CNP setup.

When you build your bench harness for tuning outside the vehicle, it may just be worth your time to buy one. Ebay has one for $40. I built mine for damn near nothing, but I had a lot of crap laying around. A google search for 0411 bench harness will give you links to buy one or instructions to build one, your choice.

My recommendation is to just run CNP from the beginning. It's easier when you have the harness in your hands instead of the truck...

 

[TubeTruck]

keep in mind it’s more than a segment swap when you go CNP. You’ll have to replace the crank tone wheel under the timing cover and re-pin the injector order to account for the LS firing order being different. You’ll also have to run a whole new ignition harness and remove the old ignition stuff that ran behind the intake. I’d suggest provisioning and labeling the necessary wiring now while the harness is out and there, before it’s all freshly wrapped. You should only need to swap two sets of wires for the injectors and you can have the ignition harness run all the way to the coil pack harness plugs at the valve covers and even pinned into the 0411 so it’s just a Clío in and go situation. EFI connection sells the right connectors and pins for pretty cheap.

Yup, I am aware of the reluctor change but not the repinning of the injectors. Good to know. Now you got my wheels turning. I think I'm going to run another 4 wire distributor harness in with the current one. That way when I switch to CNP I can unplug distributor connector and plug in the CNP harness for the passenger side and plug another harness in the spare for the driver's side and plug the pins in the PCM. I'll have to look into that.

 

[TubeTruck]

My recommendation is to just run CNP from the beginning. It's easier when you have the harness in your hands instead of the truck...

I would love to but my 350 is quickly dying and I need to get another engine in. I'll look into the cost but it looks like it's at least another $500-$1k to do it now and I don't have that cash.

 

[Catbox]

You guys are way above my head.
I have a L-29.
But it will get a simple Holley 780 carb I bought for $100.
A rebuild kit, some jets, and an O2 gauge will be enough to get me lit off and running.
Later on I want to put in the Edlebrock Pro Flow set up.

 

[TubeTruck]

You guys are way above my head.
I have a L-29.
But it will get a simple Holley 780 carb I bought for $100.
A rebuild kit, some jets, and an O2 gauge will be enough to get me lit off and running.
Later on I want to put in the Edlebrock Pro Flow set up.

Why put the pro flo when your have the EFI already? Save your money and use the factory EFI. It's good to 550hp or so.

 

[Markmx6]

I would love to but my 350 is quickly dying and I need to get another engine in. I'll look into the cost but it looks like it's at least another $500-$1k to do it now and I don't have that cash.

I totally get that.

Here is the pricing as I see it for a Vortec to CNP

Reluctor wheel $175 from Efi Connection
Crank sensor $10 from Amazon
PCM pins $10 from either Efi Connection or Mouser
Coils and connectors $Varies depending on the junkyard, mine cost $60
PCM You area already getting one of these it looks like and if it came from an LS based engine already then the cost is just tuning (2 credits). If it is tuned for the Vortec then HPtuners would be 4 credits at $50/ea. EFI Live may be different... it may be cheaper to just buy a PCM from an LS engine as they are a dime a dozen...