Results 1 to 8 of 8

Need help with LT1 and TBI

This is a discussion on Need help with LT1 and TBI within the LT1 forums, part of the Vehicle Specific category; Ok, hope you guys help me out. My budy has a 1991 firebird that had the mighty 305 chevy engine ...

  1. #1
    98z28 hiramsuito's Avatar
    Join Date
    Feb 2006
    Location
    Arizona
    Age
    34
    Posts
    57

    former bright green
    98 z28

    Need help with LT1 and TBI

    Ok, hope you guys help me out.
    My budy has a 1991 firebird that had the mighty 305 chevy engine with the TBI setup.
    Now he decided to drop an LT1 into it. The block is in there but now he's deciding to stay with the TBI setup. He has the LT4 carburetor intake that I bought from ebay. Heres the link :

    http://cgi.ebay.com/ebaymotors/ws/eB...179552097&rd=1

    It fits so good but now we don't know how can we make the TBI fit.
    Do you guys know of a spacer or an adapter that may fit?

    Also do you guys recommend me to stay with the TBI or just go with a carburetor? and what kind of pcm or chip mods do I have to do?

    I thank you guys for helping me.

  2. #2
    Senior Member 5.0THIS's Avatar
    Join Date
    Oct 2001
    Location
    Colorado
    Posts
    3,704

    red
    95 Z28

    Well, if you continue to use the TBI, you're going to lose ALOT of performance. Those things just arent well suited to supporting that level of power (those particular TBI units). In this case, if you're not going to use the factory LT1 injection setup (which would be the best option IMO)... then go with a carb. If you use a carb, I'd also recommend going to a standard SBC style HEI distributor. If you go with the standard type distributor and carb, then you wont need a PCM for any engine controls, unless you have an auto tranny that requires it.

  3. #3
    98z28 hiramsuito's Avatar
    Join Date
    Feb 2006
    Location
    Arizona
    Age
    34
    Posts
    57

    former bright green
    98 z28

    Well, we are still deciding to go or not to go with a carb or a tbi. We know we will lose power with the tbi but it's suposedly better for fuel economy. The firebird is an auto and it still has the original tranny and I don't think it will need the pcm to work. On the other hand putting the lt1 oem injection would need the pcm, but aren't we gonna be lacking of sensors? I would really go with a carb but I'm not the one with the money so it's up to the owner.
    Thanks for your help 5.0THIS

  4. #4
    Catfish for Breakfast Bobby97SS's Avatar
    Join Date
    Jan 2007
    Location
    Austin, TX
    Age
    61
    Posts
    574

    white
    97 SS

    Where exactly are you going to put a standard HEI distributor on a LT1?

  5. #5
    Senior Member 5.0THIS's Avatar
    Join Date
    Oct 2001
    Location
    Colorado
    Posts
    3,704

    red
    95 Z28

    Quote Originally Posted by Bobby97SS View Post
    Where exactly are you going to put a standard HEI distributor on a LT1?


    In the same place it is on any other small block chevy. You can actually adapt one to a standard LTx manifold, or use one with a carb manifold.

  6. #6
    Moderator Firebirdjones's Avatar
    Join Date
    May 2006
    Location
    Arizona
    Posts
    12,552
    Quote Originally Posted by Bobby97SS View Post
    Where exactly are you going to put a standard HEI distributor on a LT1?
    Lt1's are still capable of running a conventional distributor in the rear, block, cam, etc...has all the provisions for it,,,,it was never lost,,,,,all GM did was cast the fuel injected manifold without the hole.

  7. #7
    98z28 hiramsuito's Avatar
    Join Date
    Feb 2006
    Location
    Arizona
    Age
    34
    Posts
    57

    former bright green
    98 z28

    Thumbs up It's almost done

    We decided to go with the TBI unit by putting an adapter and a normal style distributor. Unfortunately we haven't been able to start the car. We now have to get a power steering, ac and alternator bracket for the old 305 components. Everything looks so fine until now and that LT4 manifold really stands out for itself. I'll get some pics as soon as I can to show you.
    Thanks for all your replies you guys have been very helpful.

  8. #8
    12.36@109 Red on Red WS6's Avatar
    Join Date
    Nov 2005
    Location
    Tulsa OK
    Age
    38
    Posts
    454

    Red
    1996 Trans Am

    Quote Originally Posted by hiramsuito View Post
    tbi but it's suposedly better for fuel economy. 5.0THIS
    Where did you get this piece of info? Very interesting choice, I have to say this is the first time I have ever heard of anyone using a TBI for an LT1. I would have looked into a different cam profile and computer tuning myself. Keep us posted on the progress.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •