454-carb'd to replace 4.3-tbi and to become 454-tbi

[54inches]

OK, so here goes.

I have a 1985 454 out of my Suburban that I am keeping to drop into a S10 for my son. I also have a 700r4 Raptor that will be going in there as well.

I also have a 454 tbi computer out of a late 80s truck. I also have the distributor and some of the other stuff.
My 1985 454 has been converted to serpentine off the same late 80s 454.


OK, so here are my thoughts:

I want to drop the 1985 454 in a late 80s early 90s 4.3 S10.

These s10s came with 700R4s.

Now, my thought is unplugging all of the 4.3 sensors, plugging them into the 454, plugging in the 454 computer and BAM. It should work.

The reason I think it should work, in theory, is that I did a similar swap in a 1988 Chevy truck. I was the original owner and it had a 4.3 with a 5 spd manual. After 260k miles, it gave up.

I got a 1993 350, rebuilt it, dropped it in with a new clutch and it worked; even without changing the computer......

Thoughts.....

 

[Russell]

It won't run properly even with the 454 ECM.

The carb cam profile is not EFI friendly.

 

[54inches]

Thanks Russel, good point!

Stock 1985 Carbed cam specs:

192/203 dur, 398"/430" exh lift, 110.5º LSA

Entry level 1990ish 454 tbi cam upgrade:

210/218 and lift is 485/490 115 LSA

Cam swap and done.

I'll do more research of course, but that was a simple fix.

Oh and I am rebuilding the engine anyway and upgrading to 049 Heads that I have on the shelf......

 

[Russell]

Yup! Just try to build the engine relatively close to what a stock TBI 454 would be like unless you planning on doing some tuning... TBI engines are not overly hard to tune, but require you purchase some equipment to do so. Moates.net has almost everything you could imagine for tuning TBI rigs.

The tables in the ECM are programmed to match very specific flow characteristics exhibited by the engine they were set up for and makes a great deal of assumption based on those tables. When you change the cam, heads, compression ratio etc you totally change those flow characteristics and the assumptions the ECM make no longer fit. If you want decent mileage and performance from a modified TBI engine you really must do some tuning. This is one of the faults of a speed density system like TBI.

An engine that runs a MAF is much more accepting of changes in flow as the flow of air is actually measured instead of assumed.

 

[black dawg]

Entry level 1990ish 454 tbi cam upgrade:

210/218 and lift is 485/490 115 LSA

Cam swap and done.

I'll do more research of course, but that was a simple fix.

Oh and I am rebuilding the engine anyway and upgrading to 049 Heads that I have on the shelf......

When I did my 454 swap, I thought that my motor was mild enough to not need tuning (stock vortec cam and 781 heads) I was wrong. It doesnt run BAD, but it isnt right, and a big fuel pressure increase was needed to keep it from burning up. Honestly, If you are building anything but a bone stock tbi motor, I would plan on tuning and hope that maybe you wont need it.

 

[dyeager535]

Got the throttle body off the 454? Only big thing I see as necessary for your idea that you didn't specifically mention.

Still not up on the TBI ECM's that much, but if using knock sensor that is likely different, spark module, etc. Little stuff.

 

[454Sub]

You must get a 454 throttle body, and the IAC will be different. I just cut and spliced the 454 IAC to my factory 350 harness. 4 wires, just the plug is different. You will need a manual or look up what each wire does, as Im 90% sure it was not match up the colors type wiring fix. You must also use a 454 knock sensor if your computer uses it, the knock sensors are different for each motor as well.

 

[54inches]

Yep, I had a 350 with 454 TBI and just injectors back in the day, so yes that would be a given.

Thanks!

The deal is, I can either go this way or I can find an older Carb'd S10 and not worry about everything.

I am just finding some early 90s S10s right now and they are cheap and in great shape.

I don't want to mess with bodywork and painting right now, since this is going to be his first vehicle.

I know tbichips.com has some great info and I can get a nice chip from them, but not sure I want to get into all of that....

 

[Russell]

I know tbichips.com has some great info and I can get a nice chip from them, but not sure I want to get into all of that....

I'd be cautious with Brian over there. The guy has had a lot of issues lately... He has stock engine tunes down, but anything modified he seems to be having issues getting them to run properly.

 

[54inches]

Thanks Russel!

I think I am just being paranoid about our county and emissions testing; the whole point to this thread really.

I am hoping to move before he can drive over to the next county where they have limited testing.

With that said, I hate putting antiquated technology in a newer vehicle that is going to be road worthy, especially if that antiquated technology was not stock in said vehicle.

I found another 93 last night that has a 9 on body and interior.

4.3 CPI with a 5 spd manual. He wants $1800 for it and outside of it being red and having fugly wheels, it is a good vehicle.

The only other caveat is that I am looking for a good roller; which rarely exists in this world unless it is a race car. lol

 

[4X4HIGH]

Not sure about you but I don't think i'd be willing to give a kid an S-10 truck with a BBC, just saying.

 

[54inches]

Why not?

230hp BBC is not any faster than the 4.3 it replaces.

This will be his first vehicle as it is cheap and we are going to build it together.

As he becomes more mature, he will get a better vehicle and the S10 will become my bracket racer.

 

[Larry]

Why not?

230hp BBC is not any faster than the 4.3 it replaces.

This will be his first vehicle as it is cheap and we are going to build it together.

As he becomes more mature, he will get a better vehicle and the S10 will become my bracket racer.

It would sure be cool first project though! I remember back in the late 80’s or early 90’s there was a feature in Sport Truck Magazine of a, new at the time, white S10 with a period correct TBI 7.4L. Man that truck was cool and looked so factory. Under the hood was ALL engine

Although not an S10, I did a TBI 4.3L to TBI 7.4L (carb’d intake with a TBI adapter) swap last winter on my FIL’s C1500 Sportside. It turned out pretty cool but I wouldn’t say it a major fast machine. Hell, a late model 5.3L Silverado would probably whip its ass from stop light to stop light but the 7.4L is not short of tire smoking low end torque and just sounds so mean . Not sure how long the NV3500 trans or 10 bolt rearend is going to last though

Story of my 4.3L to 7.4L project here

 

[54inches]

Sweet! Thanks for sharing.

Yep, this is more for his knowledge of how to adapt and do basic wrench turning.

I don't want to go all wild with the engine for tunability reasons and for the concern that the California hippie brought up. : Just kidding hippie.

Life is so much easier when you have a cool car.

 

[4X4HIGH]

Why not?

230hp BBC is not any faster than the 4.3 it replaces.

This will be his first vehicle as it is cheap and we are going to build it together.

As he becomes more mature, he will get a better vehicle and the S10 will become my bracket racer.

TRUST ME, a 454 chevy in place of a 4.3 is a HUGE difference in a small vehicle. If you don't/can't understand that then maybe someday you will.

 

[54inches]

Listen Jackwagon, the 454 weighs about 300 lbs more and only has about 30 hp more. Yes it has about 150 more in torque, but come awn dude.

Take your rant elsewhere as I don't care.

I have built several of these 350 s10 swaps and if a mild 350 doesn't do it, then a stock 454 is not going to do it.

Oh, and I don't care how you do it in California.

 

[black dawg]

I know that your probably just using what you have or can get easily, but it seems like an awful lot of work to put a big block in if it isnt going to run any harder than a 4.3

 

[4X4HIGH]

Listen Jackwagon, the 454 weighs about 300 lbs more and only has about 30 hp more. Yes it has about 150 more in torque, but come awn dude.

Take your rant elsewhere as I don't care.

I have built several of these 350 s10 swaps and if a mild 350 doesn't do it, then a stock 454 is not going to do it.

Oh, and I don't care how you do it in California.

Not going to argue with you since i'd obviously get nowhere but to start calling names is uncalled for. Hope you don't EVER need help from me cause you'll NEVER get it.

 

[DEMON44]

Listen Jackwagon, the 454 weighs about 300 lbs more and only has about 30 hp more. Yes it has about 150 more in torque, but come awn dude.

Take your rant elsewhere as I don't care.

I have built several of these 350 s10 swaps and if a mild 350 doesn't do it, then a stock 454 is not going to do it.

Oh, and I don't care how you do it in California.

You know this fella you're so rudely calling down has already forgotten more about building Chevy v8s than you and your kid will likely ever know.

Pull out a mirror if you're looking for the jackwagon captain.

 

[54inches]

I know that your probably just using what you have or can get easily, but it seems like an awful lot of work to put a big block in if it isnt going to run any harder than a 4.3

Ohhhhh...don't get me wrong, for him it will be mild; for me it will be turbo'd, tubbed and a dedicated bracket truck.....