TBI swap from '88 to '87

[87Lowrider]

Board member bought an '88 3500 GMC w/454 TBI system. He is going to put it in an older truck and put a carb on it. I'm considering swapping him my factory '76 454 intake / q'jet carb for the TBI w/ecm and put it on my '87.

Will the '87 harness plug into the '88 TB or do I need to jump through hoops to get it done??

Thanks!

Ken

[BLE 'BURBAN]

I'd get the full harness off the '88 model under hood and under dash and just swap everything.

[Hoods69BadBowTie]

Originally Posted by BLE 'BURBAN

I'd get the full harness off the '88 model under hood and under dash and just swap everything.

x2 will make it easy and be done with it the first time.

[87Lowrider]

I think he has that... we'll see!


Thanks,


Kenny

[Captkaos]

You don't need the harness, you already have one. Just plug it all back up, get his chip and injectors and you are done.

[87Lowrider]

Originally Posted by Captkaos

You don't need the harness, you already have one. Just plug it all back up, get his chip and injectors and you are done.

Great, I was hoping that was the case... When we work the deal, I'll have the ECM too and I think the Injectors need some work if not replacement.

Thanks Chris!


Kenny

[454HO]

Kenny, the factory TBI system may not be able to support your HP level. I think the stock TBI engines are only 260HP or so. Don't you have a healthy cam and some other goodies in your engine?

[87Lowrider]

yea 500hp...didnt consider that


Ken

[BLE 'BURBAN]

Originally Posted by 87Lowrider

yea 500hp...didnt consider that


Ken

You may want to check out this site.... http://tbichips.com/

And if you're looking for even more power from a blower setup for a TBI unit check out this one linked thru the one above http://www.tbi-superchargers.com/

[Captkaos]

The TBI can be setup to handle 450hp with the right components.
did you dyno the truck at 500hp?

[87 STEPPER]

If your SBC is pushin 500HP then i seriously doubt you will be happy with the performance output of a stock TBI 454.

[87Lowrider]

Originally Posted by BLE 'BURBAN

You may want to check out this site.... http://tbichips.com/

I'll Bookmark those and check them out tonight... Thanks!

Originally Posted by Captkaos

The TBI can be setup to handle 450hp with the right components.
did you dyno the truck at 500hp?

no... just an estimate based on dyno 2003 software. It feels pretty strong though.

Originally Posted by 87 STEPPER

If your SBC is pushin 500HP then i seriously doubt you will be happy with the performance output of a stock TBI 454.

I don't know if that was a typo but I have a BBC now not a SBC. You're correct, I won't be happy to go backwards... I didn't do all of that work though and spend all that money to starve the motor with the factory tbi. This was just a thought if it'll work and my performance doesn't suffer. Otherwise, I'll buy a whole tpi system from edlbrock or somewhere. This is my winter project for the lowrider.

[gchemist]

Another good tbi website.
http://www.cfm-tech.com/GM_tbi_tuning_tips.htm

[87 STEPPER]

Originally Posted by 87Lowrider

I don't know if that was a typo but I have a BBC now not a SBC. You're correct, I won't be happy to go backwards... I didn't do all of that work though and spend all that money to starve the motor with the factory tbi. This was just a thought if it'll work and my performance doesn't suffer. Otherwise, I'll buy a whole tpi system from edlbrock or somewhere. This is my winter project for the lowrider.

No it wasnt a typo. lol i dont look at every ones sig info and i should have that time oh well i didnt know you were runnin a BB.

Is this swap for fuel savings or other reasons??

[Captkaos]

I am sure you have probably posted this, but what are the specs of the motor? Reason I ask is Dyno 2003 has been real generous when I have had a few people play with it.

If you motor isn't setup for less than 5500rpms, and you don't plan to change it, I would move to another TB setup.

[87Lowrider]

Originally Posted by gchemist

Another good tbi website.
http://www.cfm-tech.com/GM_tbi_tuning_tips.htm

Thanks! - I'll check it out!!!

Originally Posted by 87 STEPPER

Is this swap for fuel savings or other reasons??

Fuel savings would be the number one reason next to the coolness of having fuel injection on the BBC when I open the hood.

Originally Posted by Captkaos

I am sure you have probably posted this, but what are the specs of the motor?

The block is stock on the bottom end. I really don't plan to rebuild it unless I absolutely have to.

It is a 1976 Chevrolet 3/4 ton 454 (std bore), Cast Iron Oval Port 781 heads with 2.190 / 1.880 valves with at least a 3 angle job, Comp Cams XE 274h 552/550 lift 286 dur. Comp Cam Full Roller Rockers, MSD Pro Billet Dist, MSD Digital 6 Ignition, MSD HVC Coil, MSD 8.5mm Wires, EdelBrock 1407 750 carb on a Edelbrock Air-Gap Intake. Dyno 2003 shows 488hp / 466ft lbs @ 5500. I have yet to get it up that high yet though, so I don't know if it'll do 5500 or not.

[Captkaos]

That cam range is 1800-6000, you would definitely need a chip burnt for it, and you would have to run the fuel pressure way up to about 25lbs and you would have to mod the TB...

[87Lowrider]

Originally Posted by Captkaos

That cam range is 1800-6000, you would definitely need a chip burnt for it, and you would have to run the fuel pressure way up to about 25lbs and you would have to mod the TB...

OK.

What Would be best, the stock TBI or should I consider something aftermarket??

I know Holley and Edelbrock make 'em.


Kenny

[Captkaos]

How much you have to spend? How easy do you want to tune it? Will you want to play with the ECM?
The only thing that is sorta out of place it the Lobe seperation. ECM's usually like 112, and that cam is 108. I will work though.

[454HO]

To me, throttle body injection has a pretty low coolness factor on a performance engine. I would rather see a double pumper carb. Now a nice custom multi-port injection setup... that would be the ultimate coolness.

But if TBI is what you want, look into just getting an adapter plate that lets you mount the TBI unit onto your existing manifold. I know they are available for spreadbore Q-jet intakes, but not sure about square bore intakes like your Airgap.

If you do get a TBI manifold, my guess is the runners would be matched to the small peanut port heads. These small intake runners and the stock 640cfm throttle body will start choking your 454 by around 4500rpm. You may be able port the intake runners to match your 781 heads, and you can get a ported throttle body that flows 720cfm. Yes you can make it work, but you will still be limiting your HP potential.

[Captkaos]

I like this for Coolness. IDI Hilborn style.


you won't really be able to see a carb under the air cleaner though. And if it is a street driven vehicle, I would much rather have EFI of some kind rather than a carb setup.

[87Lowrider]

ok... I'll take 1 multi-port setup please! - to go!

Knowing my setup now... what do you recommend guys (parts list)?

I could leave the 750 and the air gap on there.

I just thought a nice multi-port system would let me squeeze what little fuel economy I can out of the motor while maintaining as much pwer as possible. The TBI was a gimme but probably not feasible from what I'm hearing.

I'm ordering a new 700R4 from TCI this week and B&M converter. Gonna put it in next weekend.

Kenny

[Captkaos]

How much do you have to spend? EFI is expensive...

[87Lowrider]

Originally Posted by Captkaos

How much do you have to spend? EFI is expensive...

enough ... are there complete systems out there or do you have to piece them together or should I hit the salvage yard?

[454HO]

The '96-'00 Vortec 7400 intake would be a better factory choice than TBI. You would probably need to modify it with bigger injectors and adjustable fuel pressure regulator, then get a custom tune. But this intake does use the large oval runners and should flow enough air to get 500HP or so. You could pick this up on eBay or perhaps in a juckyard for less than a grand. But count on having to replace defective sensors, broken connectors, etc, etc. So the cost could go up.

And yes there are several turn-key aftermarket bolt-on kits. Some are probably better than others. Personally, I would stay away from Holley or Edelbrock controllers. Look at FAST. Their controller is probably the best on the market... but it is very expensive.

You could probably piece together a better (cheaper) system by buying a manifold, fuel rail, injectors and throttle body of your choice. Then get a FAST controller and have a wiring harness custom made. This is what I plan to do eventually, but I would use a Megasquirt controller and make my own harness.