I have several questions but im only gonna post a few. I would do a search but id be here all day so i just wanted to catergorize them in one post. Im fixing to buy a 91' with a LO3 and 700r.

Where to get a larger injector?
What ECM does a 91' LO3 use?
Can i use a Vortec prom?
Wheres a link to LO3 "free mods"?
Wheres a link to interchangable intakes?
" " " " " " carbs?

Im really sorry for the common questions but ill be searching for awhile.

 

https://www.thirdgen.org/newdesign/t...imatetbi.shtml
https://www.thirdgen.org/newdesign/t...matetbi2.shtml


Free mods

 

I believe you can buy bigger injectors from GM.

8746 ECM.

Dunno about the vortec Prom.

And the rest has been covered

 

Why do you want bigger injectors? There is really no need for them unless you motor is heavly modded with like aftermarket heads. It would probably do more damage than good. The best thing to do is adjust the fuel pressure, which will give you significant gains.

As for all your other questions just go to the tech artical section on the homepage of this website. You'll be able to find all kinds of useful info on free mods and swapping intakes.

 

How many injectors are there? I have a 355 ready to go in the garage for when the 305 goes out. I also have a set of Vortec heads waiting on me. Thats why was asking about the interchangeable intakes and carbs.

 

not really sure. i think one size for 305, two sizes for 350, and three sizes for 454. look at holley web site. they have variety of sizes. largest is 90lbs(GM).

 

What cam are you going to be running with that 355? You are going to want to match your injector choice to what you expect to be making in horses. Stock vortecs or ported?

You can basically use any carb intake manifold and use a TBI adaptor plate to fit the TBI on there. Honestly though, with a fairly built vortec 355 you are going to want to buy a Holley 670cfm TBI unit #502-6. That unit comes with 85pph injectors I believe. You will also need to up the fuel pressure on that and in turn need an aftermarket fuel pump. Many go for the Walbro 255 because its pretty cheap and will supply all the fuel you could possibly need.

As for the prom you have an 8746 ecm and need to make your own custom prom for that motor otherwise it will never run to its full potential. Look over on the diy-prom board about burning your own chips and get started asap if you're really serious about running TBI on this engine. Some have also gotten by using chips from www.tbichips.com but I think a lot is to be gained over those chips by burning your own no matter what your experience level.

 

Thanks alot for the info. Is the prom the same design (physically) as my LB9 prom. If so can i use the same burning hardware for the TBI and my TPI. It would prolly be cheaper for my to just run carbed? Im fixing to get back to a local guy about a 86' Z with a LB9. The cars complete except for the interior being completly stripped and the body being ruff. He only wants $750 for it. But if the motor and trans runs good im just going to use the TPI out of it. Not to mention it has a 3.23 rear with disc. Ill get back in a day or so. Thanks