Swap to an 8.1 Vortec?????

[Green79Scottsdale]

What's wrong with the current Vortec 454 fuel rail injection system? I hear it's upgradable with Furd Injectors and such. It's not like the 350 Vortec with a spider assembly under the intake. It's my understanding it has fuel rails that the injectors can be changed and such? And then chip it, blah blah blah? Or am I missing something? Will it not bolt onto an 8.1?

No, that assembly will not bolt to an 8.1. The top ends do not swap betwix the traditional big block and the 8.1. When you say current, you realize the Vortec 7400 was out of production by 2001, don't you?

He could however swap it onto his current 454. But if he is going that far I would source a complete engine. They are the last iteration with all the goodies like roller cams and very nice flowing heads. More aftermarket support than a 8.1 also.

 

[OkieFishMan]

What's wrong with the current Vortec 454 fuel rail injection system? I hear it's upgradable with Furd Injectors and such. It's not like the 350 Vortec with a spider assembly under the intake. It's my understanding it has fuel rails that the injectors can be changed and such? And then chip it, blah blah blah? Or am I missing something? Will it not bolt onto an 8.1?

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So many options my head is starting to spin........

 

[OkieFishMan]

No, that assembly will not bolt to an 8.1. The top ends do not swap betwix the traditional big block and the 8.1. When you say current, you realize the Vortec 7400 was out of production by 2001, don't you?

He could however swap it onto his current 454. But if he is going that far I would source a complete engine. They are the last iteration with all the goodies like roller cams and very nice flowing heads. More aftermarket support than a 8.1 also.

Yeah, I could see where it would be worth it to pull a complete engine from the salvage so I could have everything. Holy smokes I have options! Decisions Decisions........

Are the vortec 454s (vortec 7400) very tunable if you were to install a different cam?? I know nothing about the world of EFI tuning.

 

[Honky Kong jr]

Yeah, I could see where it would be worth it to pull a complete engine from the salvage so I could have everything. Holy smokes I have options! Decisions Decisions........

Are the vortec 454s (vortec 7400) very tunable if you were to install a different cam?? I know nothing about the world of EFI tuning.

The 454s have minuscule intake ports and little valves and low compression they are designed for torque and peak out at roughly 4200rpm.

 

[yevgenievich]

The 7.4 version in 97 one ton crew cab i had, worked very well pulling 8k load at 75mph without having to down shift from 5th gear. Compared to how my 91 suburban handles the same load, it was a 1000% improvement. (Full throttle in 3rd gear up a hill at 60mph in the suburban).

 

[sdwolff98]

Yeah both the Vortec 454 and the 8.1 vortec motors can use the 502 ramjet camshaft On the 8.1 you just have to do a lil rewiring on the computer to accommodate the swapped cylinders lol.... I am putting one in my 64 GMC right now allison and all
http://67-72chevytrucks.com/vboard/showthread.php?t=438342&page=10
I did find the headmenn elite 67-87 big block headers will work for this critter.

Sean

 

[aaronvogel]

From what I understand I'd have to notch the frame a bit to clear the factory 8.1 exhaust manifolds.

No, no, no, no, no! Don't go choppin' up the frame for this swap. I'm in the middle of it right now on a '73 'Burb. And while it isn't totally plug and play, there's 0 reason to chop the frame. The 454 manifolds will bolt right on to put the pipes in the right place, the A/C compressor relocation will avoid the frame issue there. Here's a great wealth of info on doing this with part numbers and all: https://ck5.com/forums/threads/l18-8-1l-swap-resource-thread.308019/

 

[OkieFishMan]

I think that since I already have a 1 piece rear main 454 sitting in my shop, I will just build it. I'll put a roller cam in it, could very easily buy a scat stroker rotating assembly, ditch the peanut ports for some regular oval head and freshen them up, bore it .030 over, toss on an edelbrock intake and carb and end up with a 375hp 500tq 489cid towing beast of an engine. Then I can upgrade to EFI at a later date.

 

[Honky Kong jr]

I think that since I already have a 1 piece rear main 454 sitting in my shop, I will just build it. I'll put a roller cam in it, could very easily buy a scat stroker rotating assembly, ditch the peanut ports for some regular oval head and freshen them up, bore it .030 over, toss on an edelbrock intake and carb and end up with a 375hp 500tq 489cid towing beast of an engine. Then I can upgrade to EFI at a later date.

Sounds a lot simpler that way. Just gotta watch what heads you get with that kinda displacement. You will want a open camber so the valves aren't shrouded to bad and you will want a domed piston to make up for the size of the combustion chamber size. I have 96cc chambers with domed pistons in my 407. .021" Head gaskets and I'm at roughly 10.5:1ish.

 

[74 Shortbed]

If sticking with a factory head use "781"'s put the big valves in and do a clean up "no hogging out", get the squish area down as tight as you can get by with(free horse power & torque)use the shallowest dome you can(flat tops make more power)for the compression you want, shave some off the head if needed get the highest compression you can for the fuel you plan to run..

 

[OkieFishMan]

Since it will be a tow engine, as I will be pulling 10k regularly, I don't want to get to crazy with compression, especially with iron heads. I'll prob go no more than 9:1 so I won't have to run more than 87 octane and won't have to worry about detonation becoming a problem when it gets worked hard.

What intake is the hot ticket? Performer, Performer RPM, one of the Weiand intakes????

 

[4WDKC]

Yeah, I could see where it would be worth it to pull a complete engine from the salvage so I could have everything. Holy smokes I have options! Decisions Decisions........

Are the vortec 454s (vortec 7400) very tunable if you were to install a different cam?? I know nothing about the world of EFI tuning.

THe black box ecm is harder to find someone to tune it, if you swap to the 0411 ecm from an 99-02 ish express you can use any tuner software that tunes LS engines.

 

[1984dually]

Swapped an 8.1/4l80e into my 84 Dually. Documented it at http://www.gmsquarebody.com/threads/8-1l-4l80e-swap-into-84-dually.7794 This truck has had several engines including several 454/496, 70 500 inch Caddy and even a 350. transmissions have been either a 400 or the current 4L80E. While a 454 is a good engine, nothing has compared to the 8.1L in my truck. Gets average of 11 plus pulling 17,000 lbs. Reprogramming the computer is the most important part of the swap. Everybody has their own opinion but for me I'll take an 8.1 over a 454 anytime. If you like some more info not covered in the thread pm me and I will send you my number.

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[OkieFishMan]

Swapped an 8.1/4l80e into my 84 Dually. Documented it at http://www.gmsquarebody.com/threads/8-1l-4l80e-swap-into-84-dually.7794 This truck has had several engines including several 454/496, 70 500 inch Caddy and even a 350. transmissions have been either a 400 or the current 4L80E. While a 454 is a good engine, nothing has compared to the 8.1L in my truck. Gets average of 11 plus pulling 17,000 lbs. Reprogramming the computer is the most important part of the swap. Everybody has their own opinion but for me I'll take an 8.1 over a 454 anytime. If you like some more info not covered in the thread pm me and I will send you my number.

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Thank you 1984Dually!! If I decide to go that route I will definitely have some questions. I have a while to decide, as I probably won't start this project until next summer.

 

[1984dually]

glad to help with whatever I can. Having a Manual trans will make it easier. Looking to swap my 4L80E for a 6spd as soon as I find one that I can afford.