Hey all....About to do the 305 -350 swap here in about a week and trying to line up parts. I'm pulling the factory 305 and putting in a crate 350 tpi. Am just trying to figure out the whole chip thing. Is it as simple as going to the dealership and asking for a 350 chip for a 91 Z28, or is there more involved?

Any help would be great

thanks
Matt

 

If you are using everthing from the 305 TPI set up I would get a GM stock 350 chip to start and tune the new engine. Note! make sure you have the 22# injectors to make this work. After
everthing is running smooth you can check out other chips.

 

thanks for the reply/....I was under the impression that I needed to have 24# injectors with the 350. What are the stock injectors on the 305 tpi set-up? I was just going to get new 24# injectors when I put the engine in.

 

Injector size:
305 stock-19#
350 stock-22#
reseach history on what else is needed for the 350 TPI
swap.

 

Well...I've researched this alot and know everything I need for the swap. I've just been told by several people to get the 24# injectors and/or adjustable fuel pump for the 350 tpi. Just caught me by surprise.

 

With a TPI 350 swap using the 305 computer and wiring I would not deviate to much until the engine is up and running smooth.
Also that is a Adjustable Fuel Regulator and not a fuel pump, a big differents. I went this route last year, check my signature.

 

well, I was thinking about swapping the 350 tpi, the computer chip, and the injectors all at the same time. Or do you recommend doing just the engine first and then after everything looks ok, go ahead and replace the chip and injectors?

Sorry if I sound a little confused

 

You have a lot of options for a decent beginning tune, and the advice given so far skips around a little.
If you do what is in the first sentence of above quote, you are only missing the 350 knock sensor. This important component is quite different beween 305 and 350 engines.
The 350 "chip" (for your year-91, actually called a Memcal) will also have different circuitry for the knock sensor. You can get a new Memcal for a 91 350 for about $50-$80 from your GM dealer, or from an internet parts house. You can use the 24# injectors if you want, but unless you plan major enhancements for the engine breathing, it will not be necessary. I believe the stock 22# are good for about 350 HP with stock fuel pressure, and more with an AFPR.
Installing the desired injectors during the intial build avoids a sort of PITA to change them later (the Memcal change is a piece of cake), so you can consider that.

 

I did the swap on mine. First thing I did is put the motor in and got it running, then later on I put 24lb injectors in. Then a couple months later stuck a stock 350 chip from GM ($75 non-refundable). Been driving it since, runs perfect. But could use a afpr for more power. I get around 24mpg with it. But if your going to modd the crap out of it you will definately need the afpr.
Hmm, never changed my knock sensor. Beats me car runs super.
And another thing is the 19lb injectors wont last long. So change them during your swap. You can get a set as low as $250- $450 from Summit. Dont go to Gm for them they will nickel and dime ya to death.