I recently watched my 305tbi in my '92 go up in smoke(shattered piston in cylander #5).

I have found a 350tbi out of a '91 Z28. I am going to use my accessories('cause they all work well) and brackets off my 305, I was told they will match up.

Now here's the questions.....

First....I know that I am going to have to put 350 injectors on the throttle body. I was told my 305 fuel pump would still work, will it without running lean, or should I put a 350 pump in it?

Secondly..... I have heard that I can still use my 305 wiring harness and don't have to put a chip in the ecm, is that true also?

I haven't done any swaps with fuel injected engines before, so this whole ecm thing is new to me. Any help or advice will be greatly appreciated.

Okay - first off, check out the TBI Boards - they're really knowledgeable and helpful. Second - the stock computer/wiring/fuel pump work fine - although you can benefit greatly from a modified ecm. Make sure you upgrade to 350 injectors and keep all your wires/sensors kosher. I just banged my head against a wall for a month b/c i thought my ecm and tbi weren't compatible with the 350 but it turned out to be a vaccuum leak on the intake (where the tbi bolts on).

Tyler

I replaced my 305 TBI with a 350 last year.
You'll need the 350 injectors,Knock Sensor and Module.
If you can get a chip from a Caprice, it'll work with an Automatic trans.Mine is a 5 Speed, so I needed a custom chip.
Also, getting an adjustable fuel pressure regulator (or making your own ) is recommended.
E-mail me if you need more details and part#'s.
-Rich-

I just recently checked into getting a custom chip from JET.

The 350 that is going in still has the original TBI on it.
I am going to try to use the injectors off of it for now.
I already purchased the Knock sensor

When you say that "I need a Knock Sensor and Module", what do you mean by module, the ECM?? That's the only one that I can think of. I was under the impression that if you put in a chip you wouldn't have to change it.

Let me know, thanks.

we did this to a truck where I used to work, we didnt change anything at all, just dropped the motor in and it went just fine.

The knock sensor and module are designed to work for a specific engine.A 305 sensor/module will function in a 350, but it's tuned to the knock frequency of the 305.It may allow knock that the 350 sensor and module would back off the timing to get rid of.
GM wouldn't have used different sensors and modules for the different motors if they didn't think it was required, believe me.It obviously costs them more money to not use the same thing on every motor, so from a production standpoint it wouldn't make sense. The right way to do it is to use the correct combination for the motor, your car will be happier.
The module is located on the bracket that holds the fuel pump and fan relays, on the firewall, between the master cylinder and driver's side fender.
350 Sensor: AC/Delco # 10456288
350 Module: AC/Delco # 16128261
-Rich-

IT has come to my knowledge that If you don't change the injectors or put a chip in, your engine will lean out at higher RPM's
Sure, it may seem to run fine, but when it leans out too much you can have detonation, which means bye-bye Mr. Piston. You shouldn't give this information out 'cause someone who genuinely doesn't know, could BLOW THIER MOTOR if this happens. I just wanted you to know that.

hey, he asked a question, I threw in my 2cents and stated what I have done in the past...nothing wrong with that, I never said it was the correct and only way to do it, but it did work just fine.

The information you have givin, has helped and is greatly appreciated, I see you too have a 92RS which is now a 350. Since I know they didn't make the 350 in the RS, it is good to see someone else who has done the exact same swap.
By the way,
Did you test the 350 out on the quarter to see improvements over the 305. I know that I ran a 15.5@91mph with the 305, I'm hoping to get into the 14's with the 350.
With exhaust and an open element air filter, this should by all means be feasable.

I just finished my 350 swap in April, and so far, it has been running great. I got a 350 LO5 from scoggin dickey, used 350 injectors (part # 17112493), the 350 knock module (16128261) and the 350 knock sensor (10456288). The engine has about 1000 miles on it, and is much, much stronger than the 305. I also have an adjustable fuel regulator, but dont know exact pressure readings, I scan the car with WinALDL. I used a slightly modified Caprice chip, as I have an automatic.
The rest of the specs are: Edelbrock headers and catback, edelbrock TBI manifold, LT1 camshaft, underdrive pulleys, 2200 stall converter and 3.42 posi rear. I hope to get some track / gtech times soon, but it certainly feels like low to mid 14 sec.
Let me know if I can help with any other details.