Holley TBI replacement
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Junior Member
Joined: Sep 2003
Posts: 23
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Car: 91 Camaro Rs
Engine: 305 tbi
Holley TBI replacement
I know I could do the ultimate tbi since i'm completely stock other then an open air element but this is a great deal. My friend crashed his camaro and decided he's just going to get a new car and he's willing to sell me the holley 670 tbi unit for fifty bucks.
My question is 670 cfm is overkill for the 305 right? But will it do any harm to my engine if I was to throw this in? Also would I get any power gain? And would this effect my gas mileage at all? Thanks
Scott
My question is 670 cfm is overkill for the 305 right? But will it do any harm to my engine if I was to throw this in? Also would I get any power gain? And would this effect my gas mileage at all? Thanks
Scott
Member
Joined: Aug 2003
Posts: 344
Likes: 3
From: Panama City, Fl
Car: '89 Formula, '97 Z28, '88 Formula 350
Engine: 305 TBI(LO3)
Transmission: TH700R4(MD8)
For $50 you'ed better not pass it up! The Holley 670cfm TB came with different # injectors for different motors. Go to http://www.Holley.com and look at the different TB's. What size motor is it coming off of? Also what part# is it? Find that out and you will know what # injectors it has. I don't think it will hurt your engine, if anything it would raise hp. But I'd say some ECM programing is a must! http://www.pcmforless.com is who I use, I'd say he is the best for the money. http://www.tbichips.com has two levels, I is $30 it removes the speed limitor & some WOT programing, II is $50 with some part throttle programing added. Don't know if he can do any "good" custom programing though. But $30 for the speed limitor removed and some programing is a steal in my book! Hope this helps, Bobby
Joined: Feb 2001
Posts: 13,753
Likes: 560
From: Cincinnati, OH
Car: '90 RS
Engine: 377 LSX
Transmission: Magnum T56
It will work pending you do the following.
I assume it is all wired corrected because your buddy had it on his camaro. So I will skip this.
Use your 305 injectors in place of the ones that it comes with. Your car will run like junk with too big of injectors (what size does it come with?). Save them though and use them down the road once you start to mod. You just saved yourself some serious cash right there. You will have to chamfer or bore out the stock manifold to 2". The stock one is 1 11/16" and will interfere with the throttle plates of your new TBI unit. You may want to spend the extra 200 bucks and get the Holley TBI intake (2" bores) or go with a carb intake with an adapter and then you can use that TBI without any problems. You will see a few HP but you are ridding yourself of one of the many weak links of these cars when you start modding down the road. And that is the important thing.
I assume it is all wired corrected because your buddy had it on his camaro. So I will skip this.
Use your 305 injectors in place of the ones that it comes with. Your car will run like junk with too big of injectors (what size does it come with?). Save them though and use them down the road once you start to mod. You just saved yourself some serious cash right there. You will have to chamfer or bore out the stock manifold to 2". The stock one is 1 11/16" and will interfere with the throttle plates of your new TBI unit. You may want to spend the extra 200 bucks and get the Holley TBI intake (2" bores) or go with a carb intake with an adapter and then you can use that TBI without any problems. You will see a few HP but you are ridding yourself of one of the many weak links of these cars when you start modding down the road. And that is the important thing.
Supreme Member
Joined: Dec 2001
Posts: 1,418
Likes: 1
From: Morris, IL
Car: '91 t-top RS; '91 hrdtp Z28
Engine: LO3;383tpi
Transmission: 700r4;very nice 700r4
Axle/Gears: 4.10 zt posi, 3.70 auburn
WHat style caps are on the injectors?
If they are the round black ones, then do like shifty said and use the stock injectors
If they are not the spherical caps, then you are in luck because they are the delphi injectors. The delphi injectors not only perform better than the older holley injectors, they are much smaller in diameter thus making for better airflow.
If you do have the delphi injectors, find out what size they are and get a chip burned at tbichips.com. the chip is only like $30 and saves the hassle of getting the stock injector pod to fit on the holley 670 base.
Definetely grab it if it's only $50
If they are the round black ones, then do like shifty said and use the stock injectors
If they are not the spherical caps, then you are in luck because they are the delphi injectors. The delphi injectors not only perform better than the older holley injectors, they are much smaller in diameter thus making for better airflow.
If you do have the delphi injectors, find out what size they are and get a chip burned at tbichips.com. the chip is only like $30 and saves the hassle of getting the stock injector pod to fit on the holley 670 base.
Definetely grab it if it's only $50
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