hello k5 blazer owners. i have a 1990 k5 and ive been pondering the thought of swapping my 350 tbi out for 454. i have come to the conclusion that if i am to do this that it would probably be best if i found a 454 tbi and computer to swap with. i have some concerns and i know of somethings that need to change but i was wandering if anybody could give me some input on how big of a change and how many things i need to change to complete this task.
CK5
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350 tbi swap to 454 tbi
- Thread starter djd62
- Start date
way to many mods needed to make this work 100% for a stock motor.
the 454 unit is realy needed when over 300hp or so from what others have said.
there is a injection section here with tons of tbi tunning info for all to read up on.
good luck and before you throw all that money at it with wire adaptors / bore out intake to fit bigger 454 unit / and full custom chip tunning read up and save money in the end.
the 454 unit is realy needed when over 300hp or so from what others have said.
there is a injection section here with tons of tbi tunning info for all to read up on.
good luck and before you throw all that money at it with wire adaptors / bore out intake to fit bigger 454 unit / and full custom chip tunning read up and save money in the end.
I did a 350->454 swap into my '87 K5 recently.
I searched for a bit and found a TBI 454 out of a running/driving 92 Suburban.
I got the entire engine including accessories, computer, and complete uncut engine/underdash wiring harnesses. I even got the air cleaner and the cruise control module. All for $800.
I used a 4L80E out of a 1994 Diesel C/K pickup. When I bought my motor, I tried to get the trans that came out of the same truck, but someone had beaten me to that part of the deal. I should have offered another $100 and tried to seal the deal that way. Unfortunately the trans I ended up with doesn't have the reluctor ring on the output so my computer is wired to the transfer case output speed sensor. This just means I can't put the truck in 4Lo without going in to limp mode. I have to tear my trans completely apart to put the $20 reluctor ring in.
I was incredibly lucky to find a 32 spline input gear at my local U-Pull-It for a NP241 I had on hand.
I put in an electric speedo cluster. I had a '81-'87 tach cluster in the truck prior to the swap and have since converted my electronic tach to house the tachometer. That is a bit of a job.
The engine fits in the engine bay without hassle. I have the stock crossmember and used the 350 engine mounts. I have good clearance.
I had to find fuel lines from the TBI to frame (454 is different than 350)
I already had a big block radiator in the truck. I used the big block fan shroud. I used upper and lower hoses for a '89 Suburban with a 454. The trans cooler hard lines hooked right up without problem.
The stock throttle cable worked fine. I mounted the '92 cruise control module on the inner fender. It was easy to wire it in to use the original cruise stalk in my truck.
I had a local A/C shop make hoses to connect the compressor to my truck.
I lengthened the Engine-transfer case strut, trans shifter rod, and transfer case shifter rod.
I had to move the trans crossmember back.
I had to get my driveline lengths changed.
I used Doug's tri Y headers. I used a heated O2 sensor in the exhaust pipe immediately behind the header collectors.
I am still using the vacuum brake booster. My intake manifold had a plug on the driver's side that I removed and put in a hose nipple for the brakes. I will convert to hydroboost if I have any trouble with the vacuum brake system.
I was going to use my built 700R4 behind the motor and use my '7747 ECM to run the 454, but after adding up all the parts I would have had to buy to make it work, it was cheaper to put in a $300 4L80E. To use the 700 I would have had to: Get a new flexplate (I don't drill flexplates), Get or make a TV cable bracket/arm (454TBI doesnt have provisions), Get adapters for my harness to mate to the 454 TBI, Get my '7747 tuned.... It adds up fast. The 4L80E is a much better trans.
The computer mounted directly into the '7747 bracket that was already in my truck.
I was lucky with my trans. It works perfectly so far. I will pull it apart soon for inspection and to put in the reluctor ring.
My swap turned out nice. It looks like it came this way from the factory. I hate swaps that look pieced together with a rats nest of wires under the hood.
The truck runs great. It has great power. It tows my boat or a dump trailer effortlessly. I get about 10mpg in town and almost 13mpg on the highway.
Before I put the motor in, replaced the pan gasket, timing gaskets, rear main seal, head/intake gaskets, and water pump. I also put in a mild roller cam (210/220 .485 lift).
If you have any questions, let me know.
Mike W
I searched for a bit and found a TBI 454 out of a running/driving 92 Suburban.
I got the entire engine including accessories, computer, and complete uncut engine/underdash wiring harnesses. I even got the air cleaner and the cruise control module. All for $800.
I used a 4L80E out of a 1994 Diesel C/K pickup. When I bought my motor, I tried to get the trans that came out of the same truck, but someone had beaten me to that part of the deal. I should have offered another $100 and tried to seal the deal that way. Unfortunately the trans I ended up with doesn't have the reluctor ring on the output so my computer is wired to the transfer case output speed sensor. This just means I can't put the truck in 4Lo without going in to limp mode. I have to tear my trans completely apart to put the $20 reluctor ring in.
I was incredibly lucky to find a 32 spline input gear at my local U-Pull-It for a NP241 I had on hand.
I put in an electric speedo cluster. I had a '81-'87 tach cluster in the truck prior to the swap and have since converted my electronic tach to house the tachometer. That is a bit of a job.
The engine fits in the engine bay without hassle. I have the stock crossmember and used the 350 engine mounts. I have good clearance.
I had to find fuel lines from the TBI to frame (454 is different than 350)
I already had a big block radiator in the truck. I used the big block fan shroud. I used upper and lower hoses for a '89 Suburban with a 454. The trans cooler hard lines hooked right up without problem.
The stock throttle cable worked fine. I mounted the '92 cruise control module on the inner fender. It was easy to wire it in to use the original cruise stalk in my truck.
I had a local A/C shop make hoses to connect the compressor to my truck.
I lengthened the Engine-transfer case strut, trans shifter rod, and transfer case shifter rod.
I had to move the trans crossmember back.
I had to get my driveline lengths changed.
I used Doug's tri Y headers. I used a heated O2 sensor in the exhaust pipe immediately behind the header collectors.
I am still using the vacuum brake booster. My intake manifold had a plug on the driver's side that I removed and put in a hose nipple for the brakes. I will convert to hydroboost if I have any trouble with the vacuum brake system.
I was going to use my built 700R4 behind the motor and use my '7747 ECM to run the 454, but after adding up all the parts I would have had to buy to make it work, it was cheaper to put in a $300 4L80E. To use the 700 I would have had to: Get a new flexplate (I don't drill flexplates), Get or make a TV cable bracket/arm (454TBI doesnt have provisions), Get adapters for my harness to mate to the 454 TBI, Get my '7747 tuned.... It adds up fast. The 4L80E is a much better trans.
The computer mounted directly into the '7747 bracket that was already in my truck.
I was lucky with my trans. It works perfectly so far. I will pull it apart soon for inspection and to put in the reluctor ring.
My swap turned out nice. It looks like it came this way from the factory. I hate swaps that look pieced together with a rats nest of wires under the hood.
The truck runs great. It has great power. It tows my boat or a dump trailer effortlessly. I get about 10mpg in town and almost 13mpg on the highway.
Before I put the motor in, replaced the pan gasket, timing gaskets, rear main seal, head/intake gaskets, and water pump. I also put in a mild roller cam (210/220 .485 lift).
If you have any questions, let me know.
Mike W
Burbdood 74
Giver of not a single damn...
HMM. All that typing, and then I realized you are talking about swapping the 350 TBI unit for a 454 TBI unit. Damnit.
Well look on the bright side, you have yet another post to your post count.....
Well look on the bright side, you have yet another post to your post count.....
and if people use the search button thay will find this info for other questions.
My first question is why?
You're not going to gain anything from this swap on a stock 350.
