I currently have a 91 RS with a 3.1L v6 but I know a person selling a 91 RS with a 305 v8... Carburated I believe.... They owner says there is some thing wrong with the fuel pump I am wanting to drop it into mine, and ditch the bod... So is the 305 worth it, or should I hold off to a 350... How would I know if it's TBI or TPI... which is better TBI or TPI??? My friend told me you can bore 305's to a 348.... would that be worth it...

I am just happy it will be a v8:lala: :lala:

 

tuned ports look like this, theres no way to mistake it

 

then nope it's not tpi then.... what does tbi look like, it might be carburated....

 

A carbed motor will look like the image below. TBI will have 2 barrels and an injector (roundish with 2 wires coming out the top) centered over the 2 barrels. You'll have to remove the aircleaner to see which one it is.

 

You need a more informed friend. Can't be done.

Whether it's "worth it" is up to you. It's a lot of work, but having a complete donor car is the only sane way to approach it.

 

it's the whole car I am buying the 91 camaro has a 305 in it... it's a RS. I was reading that a stock 91 camaro rs 305 TBI has only 220 horses?? is this true?? How many horses are you 305's kickin???

 

It is actually much worse than that. The LO3 is only rated at 170hp at the flywheel. That number is a bit off because some basically stock L03's put close to that to the wheels. However, it does have 255lb ft or torque which is always fun off the line. If you get it for a steal it will be better than your v6 but no where near 350 performance. Buy the car and use it as a project and keep your v6 as a daily driver.

 

Yeah I'll do that... thnx, for all the info... is the tranny that the 305 has in it along with the TBI and all the accessories can be hooked straight up to a 350???

 

Yup. For the most part everything is interchangable.

 

Sweet, the 305 has cruise control is there any way to take it outta there and put it in my 3.1???

 

I have a 91 RS 305 TBI car and a 89 RS 2.8.

The 305 will seem like a big block compared to your 2.8. This will wear off as you realise you car isn't really that fast. Do what everyone is telling you and buy the 91 305, use it as a project car while you are driving your v6.

If you don't do this you will be out of a car, and *** forbid that you run into a problem. There will be issues you haven't addressed too.

Issues off the top of my head...
1. Your 3.1L has a high pressure fuel pump, it is too much for the TBI and not enough for TPI. You will have to drop the tank to replace it.
2. Your tach will be off as its calibarted for a V6.
3. Wiring is gonna have to be swapped over and grafted together. This is going to be hard.


Do a search. Read everything you can about the V6 to V8 swaps and the three forms of induction.

 

Any fuel pump will work with a TBI. Pressure wise that is assuming that you want anything that peforms more than the stocker. The fuel pressure regulator will control the amount that is recieved by the injectors. More is better because the stock TBI pump is so weak. It will really come in handy when you need a pump to supply a constant 15psi+ of pressure at 5,000 rpm. That would be with a heads and cammed Lo3.

 

yeah, I my friend was telling my before I buy this car, was to take a gallon of gas with me to the car, take off the tbi, and pure some gas down into the injector, while someone trys to crank it up, if it cranks then you know the problems lyes somewhere in the fuel lines to the fuel pump, if you hear a clicking sound when you turn the key over, from near the tank is, then the pump is working, and it must be a line....

 

Not true. First you need an expensive return style regulator.
Secondly, the people that have tpi that have went carb will tell you the regulator causes fluctuations in the fuel pressure. A regular regulator will burn up the fuel pump.

 

I was speaking mostly for a TBI aplication and didn't go into a lot of detail. I was assuming he was using either TBI or TPI or whatever that uses a typical 3rd gen V8 return style. Many people run the walbro 255 with TBI and although they have it regulated to 15psi it can support 60+. The extra fuel just goes back to the tank. But if you do not have a return style you will burn up the pump like you said.

 

honestly, dont waste time with a TBI. if you want FI go TPI. i said to hell with FI all togeather and threw a carb on. you can tear out all your wiring with a carb and clean up the engine bay. i think its easier to make power with a carb, just have to tune it every now and again. i think FI is better for the daily driver though, it will start pretty much every time you want it to without busting out the screw driver to adjust the carb or playing with your choke

 

There is NOTHING wrong with TBI. Not only is it very versatile, but it is easier to work on than TPI's and Carbs. Nor is there anything wrong with the 305's. With the right knowledge you can get tons of power out of them. Most anything that will work with teh 350's will work with teh 305 since they are damned near the same.
If you want more power, start off with a holley 1000cfm and an Edelbrock FI-compatable intake manifold. Since FI's are computer controlled, you can make adjustments on a laptop. Unlike a carb, where there's lost of fine tuning, the FI's will do it for you.
Take a look here for TONS of **** you can do with the 305TBIs. They're not bad engines at all.

 

never said they were bad, just not as good. ive heard it all when it comes to 305 v 350. if your gonna spend money get the 350. more power. can argue up and down all youd like but the 350s make more power then the 305s, no problem. as far as the tbi to carb, id rather a carb ANYDAY man. all the big boy cars at the track are carbed, well most are.

 

2 barrel TBI is like a 2 barrel carb, almost worthless with a very few exceptions. The cost of making either one competent is outrageous. TBI is decent when you have a 4 barrel unit.

The 305 vs 350 argument is similar. There is something wrong with a 305 and its not the displacement. Its the valve shrouding. You have to use small valves and can't put larger ones in because of the cylinder bore.

As said earlier anything done to a 350 can be done to a 305, but don't expect near the return for your investment. A pair of modified Vortec heads and a comp XE 268 cam will yield 400 hp on a 350. Try that with a 305.

 

Dennis,

I am planning on replacing my 305 TPI with a 350 while still retaining the Tune Port Injection. What motor should I get considering being on budget. I guess I want to get the biggest bang for the buck. Also could you list a few places where I can purchase the motor and items I should replace such as the cam, heads etc.. to get optimum horsepower.

Thanks

 

You can't even completely tune a FI engine without a dyno.

 

I would go this route:
L98 Shortblock $1136 dollars form SDPC

Heads you have a few choices

Upgraded Roller Vortec

or Pro Topline heads from Shaver Racing Heads .


Cam:

Ideal is an LT4 Hot Cam.


Seriously think about ditching the stock TPI for a Stealth Ram. You can buy just the intake and fuel rails for about $400 from Jegs or Summit.

 

For right around 2000 dollars you should have about 400 hp with this setup. The stock TPI will kill some of it, that is why I stated you should get the stealhram base and fuel rails.

1.6 Roller rockers should put you at or over 400 hp.