I am wondering if the TBI engine accessory brackets from my '91 will bolt up to the vortec heads? Also, what headers work best with these heads?

Regarding the edelbrock performer intake, is there any way I could keep my TBI unit or do I have to switch to a carb with this combo?

Thanks.

 

You can buy an adapter plate that adapts from 4-barrel carb to the TBI pattern. That way you can keep TBI.

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91 RS LO3 305 Stock with Open Element, Chip, and Ultra Flow Muffler

 

You can buy an adapter plate that adapts from 4-barrel carb to the TBI pattern. That way you can keep TBI.

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91 RS LO3 305 Stock with Open Element, Chip, and Ultra Flow Muffler

 

where can I get an adapter plate?

 

Summit Racing, tell them you need the holley adaptor for square bore to TBI. They'll have the part number and it's $43 free shipping usually.

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, Jon (91 RS too many mods to list)

 

What about the accesory holes?

 

I've got vortec heads on my '91 camaro with the stock throttle body. I bought the GMPP intake with the heads and made my own adapter plate. All of the accessories work just fine. My headers are just headers made for the car. You don't need anything special. One thing you may need to look at is the EGR. The vortec heads are not set up for it. I had a custom chip made (Fastchips) and it got rid of the EGR code for me. You will probably need a custom chip anyway for the extra flow.

 

Keith, I believe it'll all fit up just fine with the Edelbrock. I'd call Eelbrock to make sure and also ask them about the EGR.

If/when you have the new PROM burned you have to do (at least!) TWO things to get rid of the EGR problem:

1) Turn "off" the EGR err/test function, which will eliminate any EGR codes

2) fix the EGR calibration to eliminate any multiplier to the main fuel curve. If you don't do this, your ECU will be calibrated lean and will adjust by adding more fuel. ie, You will get better overall operability if you turn the EGR "OFF" as far as fuel adjustment goes... Much less "tip-in" problems, etc... TRUST ME!!!! You gotta do it. The above posters new PROM mentioned may have already had this done but most companied do not do it because it SURELY MAKES THE CHIP NOT STREET LEGAL!!!

 

all accesory brackets will bolt right up.

you can get an adaptor from tubo city, www.turbocity.com . i hear that they are better than the holley one for some reason.

i like the SLP headers. stay away from edelbrock though because if you have those heads and intake you will need more airflow. and teh edelbrocks are TERRIBLY restrictive. at leats as far as i am concerned. the SLP ones are cheaper too if you consider teh coating costs. and the SLPs are available in 1 3/4". just my opinion.

i have a lot of pics and info about this stuff on my web site in my signature.

-brian

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1991 Camaro RS - ultra blue metallic, t-tops
GMPP 350 HO crate engine - TBI, MSD ignition, SLP exhaust
700R4 - 2,400 stall converter, vette servo
10 bolt - coming soon - SLP zexel torsen differential, GM 3.73s
z28boy.fbody.com
z28boy@twcny.rr.com
AIM - "Z28 Boy"

 

So is the Turbo city better than Holley for adaptor plates? I know Holley basically designed the TBI system a long time ago so wouldn't you think they would have done there homework so to speak?
From what others have said the Turbocity products are cheap.
I'm really interested why the holley is placed towards the back of the plate and not in the middle like edelbrocks replacement intake. Maybe it's because the TB doesn't have secondaries and the square bore is usually used with a 4 barrel. I'm going to do a little more research but if anybody has a good explination then please post it.

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, Jon (91 RS too many mods to list)

 

JP, have you recieved your intake and adapter plate yet. I got my air gap last week and I'm in the process of making the adapter plate with my fathers help, he has the machines to do it on. With the 454tb I am haveing to use a 1/2" plate and will have to mod the intake some so there won't be any edges to disrupt the air flow. I was wondering if the holley adapter sovled this problem and how thick it is.

Steve

 

All the parts have arrived at my home back in NJ but I'm still in Ohio till the 16th. The Holley unit is 1/2" thick with 2" bores. I'm using the holley 670cfm unit. Wasn't there some problem with the width of the square bore intakes and the large TB units? Oh well, when I get to the parts and look at them I'll make sure to take lots of pictures. My engine swap is going to be on the web real time.

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, Jon (91 RS too many mods to list)