5.7 tbi to 7.4 vortec complete swap

[chris989]

Hello All,

I have searched and get a myriad of wrong info. close not not what i am thinking of doing.

I have an 1989 350 tbi v2500 burb, I have a complete running 1996 454 vortec 4l80 burb as a doner.

I am considering swapping the entire package and I am wondering about the headaches of the computer and wiring. I can use everything from the doner but how much splicing and butchering will be involved to have the 89 work. I would run the vortec intake and injectors. I have smog test so things like the dash check engine light needs to work.

I have considered building a small block but it adds up and then to buy a tci trans controller adds more.

My 454 runs great and tows like a dream, i am just sick of the 1996, it is always leaking, squeaking and rattling.

I know "dirty larry" did a marine version and then went on to a 8.1 but i believe smog was not an issue for him???

Thanks in advance

[manimal]

Seems like a popular topic lately...im waiting for same answers...

[chris989]

Originally Posted by manimal

Seems like a popular topic lately...im waiting for same answers...

Me too, My 1996 won't sell for more than 2500 on Craigslist. It is a great truck but my wife wants something newer. I am not so worried about a few extra parts to complete it, Just do not want to dig a hole.

I have another 4l80 now to transplant but a new conveter and TCI unit will be about 1400 alone. With the 1996, i would already have it.

My concern is how much of the computer wires go back to my old dash and electronics. like the IAC counts for AC and putting it in gear. Stuff like that, if i do not know pin locations will be a real PIA.

[DirtyLarry]

Originally Posted by chris989

Hello All,

I have searched and get a myriad of wrong info. close not not what i am thinking of doing.

I have an 1989 350 tbi v2500 burb, I have a complete running 1996 454 vortec 4l80 burb as a doner.

I am considering swapping the entire package and I am wondering about the headaches of the computer and wiring. I can use everything from the doner but how much splicing and butchering will be involved to have the 89 work. I would run the vortec intake and injectors. I have smog test so things like the dash check engine light needs to work.

I have considered building a small block but it adds up and then to buy a tci trans controller adds more.

My 454 runs great and tows like a dream, i am just sick of the 1996, it is always leaking, squeaking and rattling.

I know "dirty larry" did a marine version and then went on to a 8.1 but i believe smog was not an issue for him???

Thanks in advance

What you want to do is not a whole lot different from the 8.1L I swapped into my ’89 Suburban. That system is not a marine system, although I did run a RamJet/marine ECM on my K10 8.1L for a short while back in 2008. The Suburban 8.1L swap gets going on post 186.

I’m doing a similar job in to a ’91 K5 now, which is a MEFI-4 system similar just like RamJet engines and marine but even at that, the factory TBI wire pruning is the same. If you have emissions testing where you live brings on a new bag of worms you will need to check into before starting any swap. We don't have any emissions here so it is a free for all with swapperoos.

The main tool to help you through this is a true factory GM wiring manual as you will be pruning away all of the old TBI wiring. When your done pruning the leads from the bulk head connector at the firewall that you will need are the key on power, temp sending unit, oil pressure sending unit, alternator, starter and A/C. I would also recommend getting a brand new harness to run the L29 454. Think about it, the 1996 harness is old and will be oil soaked and heat baked where many of the connectors will be really brittle. Reworking donor harness are not worth the hassle in my opinion. The best $600 you can put towards a late model engine swap is a fresh stand-a-lone harness. Oh, and you certainly do not need one of those high dollar Dakota Digital clusters like so many people think they need when doing an engine swap.

Good luck! Happy Thanksgiving

[chris989]

Did you have tuning issues with the swap. I was going to leave mine bone stock.


I am going to give the company a call next week. If the swap goes smooth it will solve a lot of my towing concerns in one step. I tow with my 1996 now and it is great.

I think the OEM numbers are ~400tq at ~3000 rpm. I like the smaller heads one the stock motors because i do not tow at WOT. Every web article is about dyno numbers and flow and in the real world my throttle is 1/2 at most.

My 96 gets ~11 mpg towing 8500 pounds. not too bad for a gas motor.

Chris

[DirtyLarry]

Originally Posted by chris989

Did you have tuning issues with the swap. I was going to leave mine bone stock.


I am going to give the company a call next week. If the swap goes smooth it will solve a lot of my towing concerns in one step. I tow with my 1996 now and it is great.

I think the OEM numbers are ~400tq at ~3000 rpm. I like the smaller heads one the stock motors because i do not tow at WOT. Every web article is about dyno numbers and flow and in the real world my throttle is 1/2 at most.

My 96 gets ~11 mpg towing 8500 pounds. not too bad for a gas motor.

Chris

Of course, there are always tuning issues I don’t care what anybody says . In fact, the tuning issues are so bad on the Suburban’s 8.1L with the RayLar cam I’m giving up on any tuners in this area and removing the cam over Christmas break then installing a new stock cam and duplicate the tune that is in the K10’s ECM. The more stock you leave them, the easier life will be. Your L29 ECM will need some tweaking too but nothing major. Those numbers you posted sound about right for an L29. L29’s are great engines. My second all time favorite BBC

[chris989]

I found this, decent information if someone is thinking of this swap.

http://www.pirate4x4.com/forum/chevy...80e-np205.html

[manimal]

Here is some pretty good info too...
http://www.nastyz28.com/forum/showthread.php?t=7811

[MTCK]

I'm doing a similar swap on my '91 only it already has the 4L80e. A few things to think about:
Transfer case - 96 drops on the wrong side, 89 lacks VSS which the trans needs.
Fuel system will need a new pump
Cooling system will likely need an upgrade, and a trans cooler
Harness is a little more $$$ if you want to keep emissions. I'm deleting EGR on mine.
Some wear items you might consider replacing are the distributor (plastic body) knock sensors, power steering hoses, oil cooler lines etc.

If you keep the stock tune tweaking the delay on acceleration enrichment supposedly pays big dividends.

Good luck!

[chris989]

Originally Posted by MTCK

I'm doing a similar swap on my '91 only it already has the 4L80e. A few things to think about:
Transfer case - 96 drops on the wrong side, 89 lacks VSS which the trans needs.
Fuel system will need a new pump
Cooling system will likely need an upgrade, and a trans cooler
Harness is a little more $$$ if you want to keep emissions. I'm deleting EGR on mine.
Some wear items you might consider replacing are the distributor (plastic body) knock sensors, power steering hoses, oil cooler lines etc.

If you keep the stock tune tweaking the delay on acceleration enrichment supposedly pays big dividends.

Good luck!

I have the original 241 driver drop TC so that is covered.
I bought a dakota digital speed sensor that is supposed to do what i need??
http://www.dakotadigital.com/index.c...rod/prd109.htm

they say it will work if i do the stand alone TCI trans controller but i hope it works with the 454 computer?

I can pull everything,,, fuel pump, radiator etc from the 96.

What are you using to tune your vortec? I can program the OEM TBI computer with my Autoprom from moates. I have considered running the 7.4 with TBI but would prefer to make it a complete swap.

[MTCK]

I can't speak to that pulse generator working or not. I asked Howell and they said my factory vss will work fine. I left it at that.

A buddy I work with used HP Tuners for turning off torque management and the acceleration enrichment delay. I haven't selected my route for tuning yet.

Will the 96 rad fit? Exhaust manifolds? EGR feeds from driver's side manifold and would require some custom plumbing if you ditch those manifolds and keep EGR or plug and block off plate if you ditch EGR.

[chris989]

Originally Posted by MTCK

I can't speak to that pulse generator working or not. I asked Howell and they said my factory vss will work fine. I left it at that.

A buddy I work with used HP Tuners for turning off torque management and the acceleration enrichment delay. I haven't selected my route for tuning yet.

Will the 96 rad fit? Exhaust manifolds? EGR feeds from driver's side manifold and would require some custom plumbing if you ditch those manifolds and keep EGR or plug and block off plate if you ditch EGR.

IF i go the 454 route i will keep it 100% OEM. manifolds, intake etc. I would like to attempt to use my 5.7 mounting accessories and keep my ac, alt, pump in the 89 tbi placement.


I might start on it this week. If it becomes to much of a headache, i will save it for another time and drop a GM crate TBI in for 1700.

I will take a lot of pics and start a new thread if anyone is interested. If it works easily, it would be a great swap for these old trucks. the vortec motors are everywhere and like my 96, they do not sell for much.

Chris

[MikeB]

Don't know if anyone mentioned this yet, but you'll have to do some research to get the motor mounts located in the proper position, and to find the correct "clam shell" motor mount brackets for a 1989 big block.

[MTCK]

Doubt the SBC accessory brackets will work on the big block. Exhaust manifolds might. I'm not planning on using the GMT400 manifolds. I know older manifolds or headers specific to the square body would, but then you would have the EGR issue.

[85raiderburban]

Originally Posted by chris989

Hello All,

I have searched and get a myriad of wrong info. close not not what i am thinking of doing.

I have an 1989 350 tbi v2500 burb, I have a complete running 1996 454 vortec 4l80 burb as a doner.

My 454 runs great and tows like a dream, i am just sick of the 1996, it is always leaking, squeaking and rattling.

Does your '89 have the SEMI floater axle? If so, youll want to swap that out with the full floater from your '96. Attempting tow heavy loads with a ("no") floater axle is a recipe for disaster.

Originally Posted by chris989

My 96 gets ~11 mpg towing 8500 pounds. not too bad for a gas motor.

Thats good mileage especially for towing. Taller gear ratio I presume?

[chris989]

It is 3.73 with the 4l80.

I do have the SF axle now, I might swap in the 14 bolt. My local driveline shop said the SF can be made plenty strong but i am with you I would rather have the FF. I am still deciding.

I have both trucks in the garage now and stripped the 5.7 down and hopefully i will pull it tomorrow.