OutlawFormula

Does anyone know if the TBI off a 87-89 454 chevy truck will work on a 91 Formula ?

Thanks

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91 Formula

snflupigus

works on a 92 rs. yes it will. but will change idle characteristics and throttle response negatively. To correct, chip programing needs to be adkusted.

Exhaust tone and mid-high rpms are improved in my opinion. Slight lowend loss with hesitation at idle - acceleration, however seems to pull harder after lag is over and injectors kick in to compensate for larger tb blades being opened quikly.

snflupigus

by the way, if you can get one of these cheaper than usual. go for it, they are very hard to find!

rsilver

snflu,do you have the 454 or the holly TBI?
I forgot your sig.Based on your comments above I wonder weather is is worth going to a larger TBI and if one should just change injectors. I had a ""programmer"" tell me it dosn't help much to go with a bigger TBI unless you are well over 300 Hp it only helps at higher RPM.( I thought he was full of s*** but I am beginning to wonder. I know Pablo had his bored out and said it was an awesome improvement but I have not heard anything more. Has anyone compared
TBI's given the same injector size?
I checked the archives and have not heard of a side by side comparason. Thanks......bob

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91 camaro RS L03 convert,
t-5, ultimate TBI mods,TBI spacer,SLP 1 5/8 headers,
3"cat back, 3.42 torsen posi,alston SFC's,Global West LCA relocation brackets

Pablo

iTrader: (1)

I didnt have it bored out i bought a used Holley 2" unit (for 60 bux!) and installed the GM injector pod on there etc

for my application, it was an AWESOME improvment, I was seeing nearly 2 inches of vacuum at high rpm, the car really woke up 3500 rpm and up

on a stock L03 I dont think it would do much at all however if you ever plan on going fast you are gonna need the TB

also youll need a new manifold or need to machine your stock manifold out to 2" bores

snflupigus

pablo is right. doesnt do much to stock lo3. i have the gm 454 tbi. I plan on doin more to the car, it was sortof my first step mod. now i plan on intake, then cam, then heads. im kinda movin down. then ill do some tranny stuff and then rearend. thats my plan. but no dont just get a bigger tbi and hope for improvement, you wont see much. actually, i might be slower now because of the lag. dont know for sure, cuz ive never ever been to track.

OutlawFormula

I work at O'Reilly and I was looking through our OEM Holley catalog.
I can buy a 454 TBI for 180.00.

I'm swapping the 305 for a 350 in march, I'm still not sure if I want to stay with the TBI or swap to a carb.

Anyway THANKS

rsilver

Pablo and Snflu. Thanks. I didn't think the 2" TBI would be much help for a stock LO3 but I was wondering if it would make a signifigant difference in a light modded 350 or vortec 350 or even in my Lo3 with the 081 heads and a decent cam and intake. IT seems logical that it would really help the top end which is where tbi is lacking in my opinion.If I go to a 350 lo5 crate or a 350 vortec do you think the bigger TBI should be on the "list"? How about if I just stick with the LO3 and do the upgrade I described above. You guys know I am back and forth with what to do, but things change and you all are always coming up with wild **** to try. Thanks..........bob
PS, glad to hear from you pablo

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91 camaro RS L03 convert,
t-5, ultimate TBI mods,TBI spacer,SLP 1 5/8 headers,
3"cat back, 3.42 torsen posi,alston SFC's,Global West LCA relocation brackets

rsilver

Pablo, I missed this point " if you ever plan on going fast you will need the TB".
Guess that answers my question.....bob