I am swapping a 1988 305 TBI into a 1989 Firebird originally equipped with a 2.8 V6 and here are some things I can not really find straight answers to, or just want to be sure I understand correctly.

1. Can the stock V6 fuel pump be used. I realize it puts out much more pressure then the TBI pump. But I have also heard that if you do many mods (LT1 cam, headers/exhaust, open element and port and polish) that you need more then factory TBI pressure. So in my case would it work better off using the V6 fuel pump?

2. The LT1 cam needs the use of aftermarket valve springs to be used in the 305 TBI engine?

3. I will need to get a 350 TBI throttle body to be successul in making use of the mods I plan on doing (LT1 cam, headers/exhaust, open element, and p&p)

4. From what I understand I will need a tune chip. Would anyone recommend getting one from the TBI tuner chip site? I do not really want to put the time or money into doing my own tuning at this point.

5. Will I need to mess with the ignition switch at all? The doner car is a 1988 with out the VATS. The car I am swapping into is a 1989 with the VATS.

6. Do the V6 Firebirds and the V8 Firebirds use the same braking system or do I need to swap master cyl. and brake booster?

Any help is always appreciated feel free to follow my progress https://www.thirdgen.org/forums/memb...sto-trans.html

 

Come on somebodys gotta be able to help me out

 

honestly man i dont have a clue about this stuff. but if anyone else posts here they are just going to tell you to go with a 350 trust me. these guys hate the 305. i would try to get info from somewhere else. maybe the f-body hideout. idk. but good luck. i like the 305 as well.

 

haha i have noticed that everyone has a 350 fetish. and thanks i never heard of f-body hideout before guess ill be checking it out

 

the v6 fuel pump will be fine,the pressure regulator will return the excess to the tank.

i dont know about the lt1 cam for a 305

the brakes are the same

if using a non vats ecm and harness the ignition switch wont matter (NO VATS)

www.tbichips.com >>>>>>>>> custom chips

hope that helps..............................

 

the 350 tbi is the same bore size with bigger injectors.

with a 305 tbi motor your problem will be the cam and heads that limit the power

 

thank you regal thats mostly what i needed to know. so i dont need to upgrade my pressure regulator at all?! thats awesome and exactly what i was hoping to hear

 

no,a lot of people swap the tbi pumps for the mpfi pumps and go to an adustable regulator after some major engine mods to get more fuel.until you get there your stock one will work. the site i gave you the link for www.tbichips.com ,brian harris, tbi is his specialty and he has a lot of info for the tbi motors.

 

cool thank you.

 

your best bet is trying to find a place that will run ur car on a dyno and burn a chip that way becasuse then its not a one shot deal they can fine tune it for you. also if you are going to have to have any machine work done id say do some head work that will allow for a better cam and then you will higher up in the hp numbers. thats what im goin to do.

 

1. Your original fuel pump delivered more FP, required by the multiport injection, then the TBI. This is good since you will need around 24psi FP with the stock 55lbs injectors to fuel your new set up. A VRFPR (wich the stock ECM does not support, but EBL does) is a must if you plan on passing sniffer, keeping carbon deposits as little as possible and not wasting lots of fuel.

2. It requires springs to support the lift of the new cam, GM or aftermarket.

3. You can use the complete intake and EFI from the donor car.

4. A coustom chip is around 200$ + a 50$ ALDL cable + some $ to ship the "test" chips back. Almost forgot; + time to datalog and sent the datalogs to the chip burner and changing the chips in the ECM.
Since you are planing to make more power with the TBI, I really have to insist that you need to upgrade to EBL flash, everything you spend for the slow ECM and its chip is wasted.
You dont really need lots of time to tune with EBL, plug it in load the bin and drive, while you drive, let it learn/adjust the VE tables, changing some values in the bin is easy too, for the set up you describe it will be a no brainer.
You get great support too.

 

Just in case you havent already found it https://www.thirdgen.org/forums/tbi/...-ultimate.html

 

what is EBL flash? I am not firmilier with that. and what is a VRFPR?

 

http://dynamicefi.com/ With the search button you will find many members feed back using it, including me. I also started out with coustom chips, belive me thats ok if you plan on removing the speed limiter and little performance upgrades only. For mild to high performance TBI the EBL works excellent.

VRPFR Vacuum refernced fuel pressure regulator http://www.turbocity.com/product_inf...roducts_id=602 , maybe you can find a way of adapting the one of your v6.

 

you wont NEED that stuff to get it running and driveable.those are to make tuning easier but not needed to run the car.

if you start to get wild with the cam and heads then you will have to look into ebl and upgraded regulator.

 

If you swap in a LT1 cam it could run yes, but at the same time it will be slower then the stock LO3.
Once you have a complete upgraded exhaust and LT1 cam, datalogging will show if you need fuel. I remember it being over 110%DC with 17psi FP @4400rpm. That was with the stock SA table.
16psi FP with stock injectors and tuned, is kinda the highest limit before it starts evaporating a noticeble amount of unburnt fuel out of the tail pipes at idle. Over 16psi the VRFPR allows it to run nice and efficient like it should, 20+psi FP with a VRFPR will be more efficient then the AFPR @16psi. Passing sniffer test with stock injectors @16psi was already a considerable accomplishment.

 

no i meant with the stock cam, i would never advise the lt1 cam without tuning.

i agree with your advice,but for the stock drivetrain swap the ebl and vrfpr is not needed.

 

ok cool. thank you guys you were a huge help and whats all the talk about the LT4 hot cam. I just heard about it tonight. Require more then just minor head, exhaust, intake and chip mods? Is it worth it?

 

id like to hear peoples thoughts on the lt4 as well.

 

LT1 and LT4 cams are wery similar, except the LT4 hot cam.
My impression is, this cam http://www.compcams.com/Cam_Specs/Ca...?csid=193&sb=2 will make more usable power in a basic 305 then the LT4 hot cam.

 

this would be a good time for a new set of front springs. your going to be adding some extra pounds to the front suspension.its a suck job but in the end well worth it.

 

I was gonna swap the K member out of my donor car