thinking: 350 tbi to 454 tbi??

I like 'stock' vehicles, and although I like stock, and prefer to leave this truck as-is (for sentimental reasons), I am also teased with the idea of getting a little more power out of it...

I did some looking around and couldn't exactly find a discussion that covered these questions...

I have contemplated doing a vortec swap which would include a GMPP TBI intake to retain the TBI and everything currently hooked up;
But another though that occurred to me is a 454(tbi) swap;

If I was to do a 454 swap (assuming I use all correct for my trucks model year senders and throttle body) what is different?
(I am aware that stuff like the TBI and injectors are engine specific)

1) Is it unreasonable to assume that a C1500 sport truck and the 454SS used the same engine loom?

2) I would assume that they both used the same ecm - but do they use the same memcal (chip)?

In my mind, those two last questions would be the biggest hurdles if a swap like this was undertaken.
(EG: what would I need to change in addition to the motor that would hook up to, or be a part of the motor?)

I am assuming that the transmission currently in my truck can be bolted behind a 454, and as long as it's period stock (read: underpowered), the transmission should be fine right?

Also, if I found a donor 454 tbi motor, what years use the same injectors/TB ec?
(EG: is a 1995 454 TBI motor the same as a 1990 tbi motor - if not, what changed from year to year)

Hopefully this isn't to big of a query.

unruhjonny said:

Is it unreasonable to assume that a C1500 sport truck and the 454SS used the same engine loom?

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Not necessarily, depending on year and automatic trans. The earlier year 454SS (and 3/4T+) used a TH400 3 speed and a 1228747 ECM. The C1500s with the TH700R4 used the 1227747.

unruhjonny said:

2) I would assume that they both used the same ecm - but do they use the same memcal (chip)?

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No on both.

unruhjonny said:

I am assuming that the transmission currently in my truck can be bolted behind a 454, and as long as it's period stock (read: underpowered), the transmission should be fine right?

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What year truck and trans?

unruhjonny said:

Also, if I found a donor 454 tbi motor, what years use the same injectors/TB ec?
(EG: is a 1995 454 TBI motor the same as a 1990 tbi motor - if not, what changed from year to year)

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Some earlier 454s used different Injectors @13PSI, 94 & 95 used smaller injectors @28PSI



Keep in mind, GM never put a light duty trans, like the 4L60 or 4L60E behind a 454. Also the 50mm 454 Throttle Body didn't come with the throttle arm for the TV cable on a 700R4, you'll need to adapt it yourself. The geometry is critical, or you'll burn up your trans in a few miles.

For a stock 350 TBI (no mods) stick with the stock 61PPH injectors in the stock 42mm Throttle Body and stick your money into a tune.

I'll be watching this, as I have an eye on a TBI 454 with 4l80.
Probably cost me the same as an LS, but those are "overdone" and who doesn't like. 454 in a RCSB???? Communists, that's who!!! Lol

have thought about this also, best option imo, buy a complete parts truck, good to go.
downside, stock TBI 454 hp/tq specs are dismal for all the work, so "a little more power" would be right.

i reconnected with an old boss of mine - from what now seems like a lifetime ago;
He disclosed what his truck was;
His was a 1990 rcsb 350 k1500 that he did a 454 swap in.
Granted he didn’t keep it even remotely stock, but that truck was AWESOME.

Regarding the transmission comment, I though my truck has the 4L80E - I would think that should have me covered if I wasn’t going for a high powered 454 - just something a bit better than the current 350.

And unless my memory is failing me, my brother has a 1995 tbi-454 taken out of a motorhome;
i know he plans on tossing the entire top end (tbi, intake, heads and loom) - so if i could get some direction here, i might be able to scoop those parts from him for a good price.

rather than re-edit my last post, lets reframe this…

if i were to find a donor 1992 k2500-454/auto;
Is it safe to assume it runs the same ecm as my truck?

I will look again at that injector chart (thanks) to see what years used the same injectors;
I was hoping that if i could find an engine which is mechanically correct for 1992 that I might be able to identify which parts would need to be changed to match my truck’s model year;
In the hopes that I might make this truck seem like a factory built rcsb k1500 454 truck.
(should i decide to go this route)

You'd be better upgrading the internals of the 350 to a 383. Put the 454 throttle body on it and have someone tune it. It'll be stock appearing yet run very near the stock 454 of that year.

You would get better fuel economy out of the 383 CumminsFever suggested than the 454 swap, but it's not a big block. I don't think a 1500 came from the factory with a 4L80 except possibly as a special order but someone else can speak more authoritatively to that. If you don't want to mess with the ECM at all, get a donor the same year as yours and swap everything you need over. Some of the things you'll need are the radiator, fan, fan shroud, radiator mounts, and the transmission cross member and drive shaft if the donor transmission is different from what you have now.

Having owned both a 454 TBI and 350 TBI, I suggest you stick with the small block. My 350 is just as quick as the 454 and delivers more than double the fuel economy. If you're not going to tow with it, the 454 only looks cooler under the hood.

DerekTheGreat said:

Having owned both a 454 TBI and 350 TBI, I suggest you stick with the small block. My 350 is just as quick as the 454 and delivers more than double the fuel economy. If you're not going to tow with it, the 454 only looks cooler under the hood.

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But sometimes the cool factor is what it's all about. I agree in stock form the TBI 454 is a pooch, but dang it...it's a big block in a small truck.
Practical, no, cool....yup.
Chevy sold every one they built.