V8Astro Captain

iTrader: (1)

I braved this crappy MO weather (rain/ice) and got another TBI unit from the junkyard. It was nasty so it's outside soaking in ChemDip, which has made me soo loopy it's rediculous.

Anyway, my buddy Dan is gonna take it to school and bore it out with a CNC mill. I found in the archives that 48mm is as big as you can go. That's good since he has an old TPI throttle body we can use the plates out of.

Anything else I should tell him to do while he's got it?


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'92 Astro, GM crate 350, Holley Pro-Jection Intake, MSD 6AL, 3.42's, 2.5" exhaust, Flowmaster 40 2 chamber, B&M 2nd stage shift kit, 255 60 R15 tires on AR-727's, Polished & Bored TBI, Custom EPROM in progress

JPrevost

Remove the ridge around the edge and maybe radius the lip so it isn't sharp. If you can, have him CNC an injector spacer out of a hard high temp plastic!
If you do that, you might need to modify the back of the TB where the fuel fittings come in. That extra metal can usually just be cut off.

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, Jon (350 TBI!)
91 Red My website

Tas

if you do the 48mm are the bores going to have the same centerlines as stock or will be be closer to the middle?

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-Tas
'89 Formula WS-6

305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options

V8Astro Captain

iTrader: (1)

They will have the same center, but a larger radius. Unless there is a better way you know of.

I made an injector spacer by taking two of the normal FM gaskets and gluing them together with RTV. Together they are 1/4
" tall, and no mods were needed to make the fuel lines work with it.

I'm gonna grind the ridge off (and radius)this one like I have on current unit. Some fancy die grinder work and finishing with a Dremel and Mothers Polishing compund worked great last time.

Tas

does the 454/670 TBI have the same bore centerlines? I thought they went in more so the outside of the bores aren't much wider than the smaller TBI?

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-Tas
'89 Formula WS-6

305, TBI, 700R4, P.A.W. 14x3 open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips, Hooker 1-5/8" 50 state legal headers, Dynomax 3" I pipe (PN 44063 and 43248)
Super GRK_Taz World
F-Body Dual Exaust
EFI & Intake Options


[This message has been edited by Tas (edited November 28, 2001).]

V8Astro Captain

iTrader: (1)

That's a good question. 48mm isn't as big as the 2"(50.8mm) bore anyway. So even if the centerlines are a little off it will still fit. It just has to be off in the right direction so they fit.

But I want it to be close. I'm gonna go take some measurements right now and see if I can come to a conclusion.

brodyscamaro

Anyway I can buy these plates from GM?



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1992 Camaro RS LO3 auto
180º thermostat, 14×3 K&N, !Cat, Flowmaster 80 series, and some audio stuff.

snflupigus

if you cant buy the plates for gm, you can get em lots other places im sure.

centerlines are same, im sure of it. 59mm if my memory is correct. if they were different, you all would sure be having some weird troubles using the same injectors pods on bigger throttle boddies

V8Astro Captain

iTrader: (1)

I'm not sure. Probably. I'm gonna call the dealer just in case we mangle one trying to put it back on.

Good call on the centerline thing Snf.

[This message has been edited by V8Astro Captain (edited December 01, 2001).]