I wanted to bore my Edelbrock TBI manifold to 2" so I could use the bigger TB. Edelbrock said you couldn't do it and all the posts on the subject on this board also said not to do it cause it would break though to the water jackets etc. Well, I
was talking to a guy here in Denver who does custom tuning and he had one that he had bored.I wanted to see for myself so I went and looked at it. He had run it on a full size blazer and I measured the holes at 1.95".
I don't know if this is a fluke or not, but it had definitly been bored and he says he knows several other people who have done it.
Anyway, if anyone is interested apparently it can be done. Maybe you just have to get lucky and get a good casting.



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91 camaro RS convert,GM crate 350 with LT1 cam,edelbrock 6085 heads,9.5:1 comp, edelbrock TBI intake, 65# injectors, GM cop chip,dual fan conversion,
ultimate TBI mods,TBI spacer,SLP 1 5/8 headers,
3"cat back,Flowmaster,
T-5, centerforce 2 clutch, 3.42 torsen posi,alston SFC's,Global West LCA relocation brackets, edelbrock STB

the original edelbrock TBI intakes could fit 2" TBIs. maybe it was one of those.

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-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Soon to be installed:
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

[This message has been edited by Tas (edited June 13, 2001).]

I don't think it was one of the 2" versions. It looked like it was bored and it was identical to my new TBI except for the 2" bores. I understand that the earlier TBI manifolds with the 2" bores were different than the current versions but I don't know what the difference was........bob

Just go with the Holley projection 2" bore TBI manifold!

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, Jon (350 TBI!)
91 Red My website

JP, Do you have a part number for that intake?

Thanks, 4-bolt

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'87 Silverado
350 4 bolt main bore .040 over
TB Injected
Ported and Polished heads
Comp cams 268h cam and top end
Flowtech headers
3.73s on Detroit locker

the holley TBI intake looks exactly like a carb version but with the top covered. you might as well get a carb intake and TBI adapter, that way you can change intakes easier or put a carb on it.

I like the edelbrock TBI intake because the bores are round all the way down to the runners. There is also a balance tube inbetween the bores. Eventually I'd like to get a Performer RPM, fill in the plenum and drill 2" bores down to the runners and drill a balance tube. That way it will be a big version of the TBI intake they make now.

------------------
-Tas
'89 Formula WS-6

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Soon to be installed:
Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248), Catco 3" cat, and injector spacer.

Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options
AOL IM: superGRtaz

Part #3704

My dad just had a stock TBI intake bored to 2", with no problems. Why would the aftermarket piece not accept a 2" bore? That sucks.

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1991 Camaro Z28
5.7L 5-Speed (originally 305)
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Webmaster: SoCal F-Bodies
-=ICON Motorsports=-

The walls on the TBI bores are not thick enough. If you bore them out you will run into the EGR passages

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92 Camaro RS, LO3, 5-spd, T-tops

Performance:
K&N Open Air Filter, Edelbrock performer TBI intake, Fastchip Prom, Timing +4 degrees, Centerforce clutch, Xact 8mm wires, SLP 1 3/4" Headers (coated), Flowmaster Catback Exhaust, Z28 Grille w/aftmkt fog lamps, MacEwen white-face guages
Electronics:
Alpine 8030 Alarm System, Valentine One Radar Detector (How did I ever drive without one?), Pioneer DEH 7450 Head Unit w/6-pack CD changer, Pioneer DEQ 7600 Sound Processor, 2 Kenwood KAC-846 Amps powering 2 12" Pro Red subs, 2 Pioneer 6x9 and 2 MTX 4x6 speakers.
NEXT UP: TBI mods, 3.42 gears w/Torsen posi

I thought you would hit the Egr passages too, but that didn't happen at least on this manifold. True, its close but it looks like there is still an 1/8 or 3/16 between the bore and the passages. Again, mabey this is a fluke..............bob