Currently i have a 91 firebird with the 305 tbi.ive done everything i can to the car and some to the engine.The car has
1.Tremec 3550 5spd
2.auburn posi w/3:73 gears
3.Steve spohn driveshaft,subframe conns,lower control arms.torque arm,panhard rod.
4.tokico illuminia 5 way adj shocks
5.eibach springs
6.suspension tech sway bars
7.centerforce dual friction clutch
The engine has
1.March underdrive pulleys
2.edelbrock intake,water pump
3.Crane cams ignition,coil,gold race rocker arms,compucam
4.Hypertech chip,fan switch,thermostat
And much more but my question is what can i do for engine replacement?What engine should i go with.What should i do with the induction?The computer?Keep it or ditch it?I want to put in something around 350-400hp whether it be a 350 or 383stroker Any ideas??????

 

getting around 300 hp or so should be easily doable with the efi. A good number of people are running some pretty fast tbi's. If your not absolutly hellbent on getting 350 + hp you could just mod your present 305, assuming its still in good shape. You can get around 250 hp with new heads, cam, full exaust, and some tuning on the ecm side. As for a replacement engine, well thats primarily up to you. Even if you keep the tbi, there are still lots of head and cam choices that you can stick on your 350 or 383. If you go carb, there are lots of engine choices there as well.

One of the first things youll want to do is decide if your keeping the tbi. If you have emmisions and/or you drive alot, youll definatly want the tbi. The tbi is good to around 300 hp or so before it becomes a restriction. Youll also need to 'burn a chip', but thats realativly easy too since there is a plethora of freeware, diy projects, and info here on TGO to help you on your way. Just make sure you dont try to build a wild motor for a carb and then stick the tbi on it. That never gets good results. Youll want to use some discretion as to cam choices and such. If you jsut want power and you dont care how much of your money ends up lining arabs' pockets overseas then the carb is the way to go. Youll be able to make alot more power then the tbi could ever possibly make. Go search around on the tbi board, carb board and the other forums. Just about every combo has been discussed.

 

Im not really sure i want to keep my TBI if it only goes to 300hp.I live in pa so i do have to get the emissions done.But i found a way around that for now.I just dont want to have to tear into my harness too much.So if i could use the holley tbi or could i just put a ram jet 350 in there?So many engines so many choices????? Or even putting a 350 tbi in there?

 

build a carb motor, thats what i did. can tear out most of your wiring and computer. its all easy bolt on and go. if you want more power, you can just buy a bigger carb. dont go over kill though. i think going carb is the easiest and you can make loads of power with it. plus its cheaper then FI i think... no injectors or runners, plenums, wiring...just bolt the carb on and go.

 

im doing the same thing right now. yankin the old 305 tbi and slappin in a vortec headed carbed 383, a fourth gen 3.23 posi uint and this summer i should be upgrading my rear brakes to the ls1's rear disks

 

also a 150 shot of giggle gas planned for next summer

 

Not that i have anything against carbs, but the tbi does have its merits as well...

Carbs are definatly cheaper then tpi, theres no doubt about that. but with tbi most of the carb parts (intakes and such) easily lend themselves to use with a tbi and the tbi ecms are very well understood. There is also the fact that the FI is infinitly variable. The timing and fuel can be adjusted for each point of the engines operation rather then over a broad range like a carb. This means that with some work the engine can be put in near perfect tune throughout most of its operation. The popular carb cams that everyone likes can also be used with the tbi, provided that the user is adept (or ***-like depending on how hot the cam is) with tuning the ecm and has a good knowledge of its operation. With tbi, if you have a good knowledge of what your doing, you can easily just about double your cars present power output and i think we all agree that the stock L03s 170 hp isnt enough for anything.

I do see that you have a good driveline behind the motor, which is a plus. As i found out, (torque+'fun') != (long term durability) with stock trans and rear. Put some power in front of them and they both crap out.

 

im not a fan of tbi at all. theres a reason why they only did it a few years in the fbodies i think the tbi chokes the motor actually. and if your going to spend the money to tune and time and all that, just got tpi. better flow and more power. but carb is easier and you can get more power with less labor and less cash.

 

glad to see the induction system debate is still alive and well. That reason is also the same reason that the other induction systems where only in F-bodies untill 92, they where mediocre performers and outdated technology. The stock tpi is no better then the tbi. It seems better largly in part because of the improved tuning, exaust, and cam profiles that the tpi's had. Both are restrictive above 4k. Compared to the TPI in the ol' GTA, Im easily matching or bettering it's performance with my goodwrench. Tuning wasnt that bad, either. After about a week of working with the bin, I had everything pretty much dialed in. Cost is cheap as well. If you have the 8746, the only investment you need make is a 150 dollars for the 'quality' prom programmer and a couple of bucks for e/eeproms and odds and ends. Virtually everything else, including the advice, is free! I also had to get software to program my 8063 but soon that too will be supported by the freeware. TBI is no slouch either. While its not the fastest induction system out there, people are running mid - low 13's with the 2 bbl tbis and cfi's. While carb and high $$$ fi systems are performance king, the tbi can offer a good mix of performance, fuel economy, and drivability when done right.

 

How about something like this?What else would i need to do to it?Bigger TBI?Different chip?


http://cgi.ebay.com/ebaymotors/ws/eB...tem=2443057590

 

you can get a similar engine thats new for less from goautocenter. http://www.goautocenter.com/300hp_tpi_1987-89.htm Youll need to do some tuning, of coarse, but with a decent exaust and intake manifold it should be good to at least 270HP when properly tuned.

 

put a bigger wing on that car and some fast and furious decals and it will go way fater.

 

If you have doubts about the TBI being enough for your intended HP , you could swap out for a TPI, harness and all. This will keep you emissions legal and preserve some of the value of the car (since they were offered with TPI)

 

oh i believe tbi can pump power, i just perfer a tpi. and i perfer a carb over both. quick, easy and fun. also, i love the smell of gas when it dumps too much into the intake carb started it all, so you have to give it credit even if your a FI man. not to mention a tbi is a carb with an injector in the middle heh

 

Hardly.

 

well thats what it looks like to me.

 

But this engine is drop in no tuning required.Think its a good deal for the money.Since both engines are going to be tbi would the one you pointed out be 300hp as well?Which one should i get with around $2500

 

I seem to remember the folks at Turbo City being an authority on TBI performance. Unfortunately their website is under construction. They would be an excellent source for parts and advice.

http://www.turbocity.com/

Check 'em out later.

 

the goautocenter one. Its completly new w/ a roller cam as opposed to the other rebuilt longblock with a flat tappet. Vis a vis theyre pretty much the same specs wise. Neither is a 'no tuning required' drop in. With the efi, youll need to tune it. Depending on the engine specs it may take up to several hundred iterations 'aka chips' to get it tuned. If you feel that your not up to tuning the efi then by all means get a carb. Just dont try to stick the tbi on w/o tuning or get one of the 'aftermarket' chips like the hyperjunk chip made by someone whose never touched your car. It wont work well.

 

outward appearences aside the tbi is a fully computer controlled fuel injection system, just like the tpi.

call me what you will but i think his car looks good. Bit too flashy for me, though.

 

i know its computer controlled but it looks like a carb with an injector in the middle.

 

I guess if you want to take the analogy a bit further it is a bit like a carb, except all the carbs functions are performed by the computer, like the accelerator pump being replaced by usecs of pumpshot. BTW, I like your avatar

 

Maybe if i had a 4 cyl or a 6(i hate ****)


Since both engines are similiar i should get the goautocenter one?Would my edelbrock tbi manifold bolt right up?As well as the acc. block(the aluminum chunk that holds the alt,pwr steering pump etc?)

And thanks dimented24x7

 

those are the tpi heads with the newer style intake bolt pattern. Itll all bolt up just like it does on your present L03.

 

I know this is off topic, but what kind of wheels are on your car?

 

heh yeah i like yours too. little bit more bold. you run tbi? all the tbi cars ive seen around here have no power. couldnt understand why GM put a tbi on a camaro or firebird...didnt produce any power so i never got into it. it must be a good system though otherwise they wouldnt keep using it on their trucks.

 

They are american racing 3 piece no longer made

 

Yep, im still runing the tbi. The only performance data I have is a 0-60 time of 6.4 seconds. Dont have any 1/4 mile times yet (dead trans) but I suspect its probably somewhere in the high 14's. I put it together as a daily driver so its more oriented towards good fuel economy then performance but it does have alot of off idle torque. With the smog heads and cam it poops out after 4.5k, though.

One reason they kept the tbi around so long is its simplicity and reliability. It has far fewer parts to fail and the parts that are there, like the fuel injectors, are very durable. Its the least complex and easily serviced FI induction system that gm used. Pretty much only have the ecm, tbi, dist. and some wires and sensors so theres not as much to break. Did i mention its easy to service?

 

So if i went with the goautocenter 350 What else would i have to get?New tbi unit?New chip?i have an intake (edelbrock tbi)And will everything else work without problems?And would i get 300hp?

 

you can probably get away with your tbi in the mean time. Tbi wise, you can do download the cop car 746 anlu bin and get some larger 65 pph injectors. That should be good for a start. If your not going to buy a chip burner right away then you can probably get someone to burn the cop car chip for you by posting an ad in the clasifieds section. Just dont pay more then 20 dollars or so since the eproms only cost a couple of dollars apiece. When you are ready to burn chips, get the burner as well as the moates switcher. Craig jsut made that available again and its definatly worth it. I have a homemade one and its worth every penny. It, as well as the moates switcher, allowes you to use eeprom and flash, which is 100x better then the old clumsy uv erase eproms. Almost forgot, youll need a 350 knock sensor as well. Not a big ticket item but youll need it.

As for the perfromer intake, the bores are set to the same size as the stock tbi so if you want to use a larger tbi down the road, which is definatly recommended, youll have to have it bored out. As for the tbi, try to get the bb tbi, its a direct swap as opposed to the holley, which requires some fabrication.

Other then a good full exaust system, if you dont already have it, and wearables like a new water pump and gaskets and such you should be good to go.

As for the 300 hp, not right away untill you get the larger tbi and get the tune dialed in. Im sure when its done up properly youll be able to get 300 out of it. Others have that same engine and they seem quite satisfied with it. Just dont give up right away, the learning curve can be a little steep at first but youll get the hang of it.