Need help with LT1 and TBI

[hiramsuito]

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.

[5.0THIS]

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.

[hiramsuito]

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

[Bobby97SS]

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

[5.0THIS]

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.

[Firebirdjones]

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.

[hiramsuito]

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.

[Red on Red WS6]

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.