I'm swapping out my 305 TBI for a 350 TBI. Will I need to buy a new chip? I'm putting in the motor soon and need to know if I need to get one ahead of time.

Thanks
Dave

 

There was never a 350 TBI in an F-body so a simple chip swap isn't possible. You need to custom burn chips or change to TPI.

 

I've done the 305 TBI to 350 TBI swap in a '91 firebird and the fuel requirement difference isn't enough that the stock computer cannot handle it as is.
If I remember correctly the knock sensor on the 350 is "calibrated" differently... so the knock sensor from the 305 will need to be used.
You are still going to have that irritating 110 MPH cut off unless you go with a custom chip.
If performance is your goal....TPI is the way to go...more work but well worth the effort.

 

For proper operation of your EST, you should get the 350 knock sensor and electronic spark control module. A 305 knock sensor and module would not be as efficient in detecting knock in a 350. It will still work without them, but not as well as it could.

 

Didn't the LO5 in GM trucks use TBI? So couldn't he get the PROM from one of those and use that? Hell, couldn't he just use the whole comp?

As for the governor, you splice a wire and run a switch for it and no more governor - takes 10 minutes. The tech article is on the thirdgen.org website.

As for TPI vs. TBI, well, that's a different argument entirely...