Is there a difference between the 5.0 throttle body and the 7.4L throttle body, flow wise?

 

hey man, hows that 327 coming?

and yeah there are. the 454 TBI has much larger bores, 2" compared to 1 11/16"

 

yep jester hit it on the nose

the stock TB flows like 400 cfm, the bigger one is 670 cfm

 

Will the larger TBI fit on the 5.0 Camaros?

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91 RS Conv. 305 TBI, 5 speed, 3.73 gears, Posi, Ultimate TBI, 3/4" TBI spacer, AFPR, 160 degree thermostat, fan switch, Open element air cleaner w/3" K&N, Accel 8mm wires cap and plugs, Edelbrock TES headers, 3" in/out High Flow Cat, Flowmaster 3" Exhaust w/3" stainless tailpipes, 245/50/16 tires and a kickin' system.

 

Yes, however your manifold needs to be bored out to 2" or you need the Holley TBI Projection manifold or you can get a carb manifold with a TBI adapter.

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My car is the perfect women. She's braless, won't talk back and loves a good beating.
1989 Camaro RS L03 w/ WC T-5
http://350.StreetRacing.org
ICQ: 61342629 AOL IM: BlackSunshineZ28

 

Seems like to me it'd be worth a look at putting on a 454 TBI unit. But does anybody know if the wiring will hook right up, and will the stock chip run the 454 TBI or will a custom chip need to be made.

Any help is appreciated,

Jason

 

I've got Holley's 2" throttle body. All the electronic connections plug right in. It seems, however, that I'm going to need a custom chip for the car to run right. It runs OK as long as you don't quickly open the throttle, but what fun is all this high performance stuff if you never open the throttle quickly?

-Mark W.
<A HREF="http://www.angelfire.com/al3/thegreycar/">'88 SC Camaro w/ 305 TBI</A>

[This message has been edited by Mark305TBI (edited September 11, 2000).]

 

Mark305TBI,

I was just wondering if you got the Holley for 5.0s (p/n 502-5) or the one for 5.7s (502-6). Also, have you had any check engine lights etc? Is the only problem opening it up too quick? I'd like to keep the TBI setup both because of cost (Accel's TPI set-up is $3000+)and because I like the old fashined look.

Any help is appreciated on fixing up a hi-po TBI setup.

Jason

PS, any performance gain?

[This message has been edited by 89BlwnRs (edited September 11, 2000).]

 

Does anybody know the first year of the 454 TBI? I have a built 355 and I'm thinking about a TBI setup, however, I used pre-87 heads.
thanks

 

what do the heads have to do with the tbi unit?

 

What Pablo is getting at is although there is a difference in intakes and heads between the '87 and '88 model years it does not effect the mounting of the adaptor plate/TBI unit on a carbed intake.

Stock TBI small block intakes as discussed before of course have smaller throttle bores and require modification to benefit at all from the larger TBI. Even with modification though, stock intakes suck so replace it with a good single plane and a GM 2bbl TBI on an adaptor plate.

How much power are you making or do you plan on making?

[This message has been edited by Dan W (edited September 20, 2000).]

 

I am wanting to go with a larger 670 cfm throttle body also, but jegs and summit both seem to think that the computer will not support it all and they also told me that I would not be able to add different heads, cam or anything b/c of the computer. Is that all true?

 

You can add anything you want and if you tune it right, it'll run, but it wont run as good as if you get the computer configured for your exact setup. My friend Greg is running the Holley 670 and pro-jection manifold with the hypertech over-the-shelf ecm. It runs strong enough. 15.5 on stock heads and cam. It only gave him maybe .1 improvement, though, because the throttle body is too large for a stock heads/cam/na engine. Sometimes being too big hurts as much as being too small. But if he ads a cam, I think we'll see larger gains than we would with just putting a new cam under the stock manifold/tbi.

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Chuck Kulchar
1991 RS
Open Element w/K&N
3" cat and Force II cat-back

 

You are refering to the ecm as the chip right? I am not up on the computer part of it. I have the hypertech stage 2.

 

if you have a 305, i think everybody should spend their money on other things besides a throttle body first, then later maybe, you might need a bigger tb unit, but not on near stock of slighly modified 305, especially if you arent burning your own chips.

 

I'll agree with 'snuff, on this engine the heads and cam are the most restrictive parts of the engine rather than the TBI. That 450 or so CFM dosen't tell the whole story either, from what i've been told EFI throttle bodies are rated at a different pressure than carbs, so in other words a 450 CFM carb does not have the same airflow as a 450 CFM carb.

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88 Camaro (The mighty LO3 SC!)
305TBI/700R4/2.73/123,XXX miles
14" Open Element and Flowmaster 80 seires

Next up: headers and gears

 

I plan to do the heads, cam, and intake before I get to the tbi....I just didn't know if you could get one and make it all work. I don't know much about the computer and its parameters. Is there any other tbi that are rated around 650 other than the holley...I have heard alot of bad things about those.