305 TBI to 350 TBI swap
Thread Starter
Junior Member
Joined: Jun 2015
Posts: 25
Likes: 0
From: Norwood, Ontario, Canada
Car: '88 IROC-Z
Engine: 305 TBI
Transmission: 700R4
Axle/Gears: 2.73
305 TBI to 350 TBI swap
Wondering if anyone can help me with situation I'm going to get into. I have an 88 IROC with a 305 TBI. I'm replacing with a 350 TBI. Do I need to find an ECM for a 350 or can I modify existing ECM from the 305?
Joined: Mar 2014
Posts: 4,556
Likes: 811
From: South Ms
Car: 89 Firebird
Engine: 355 TBI
Transmission: 700R4
Axle/Gears: 10 Bolt.Posi-3.73s
Re: 305 TBI to 350 TBI swap
You just need to get a chip burned for the bigger injectors if you are using the TBI off the 350. Same ECM. You should also use the 350 knock sensor and 350 esc module they say. I have known of people just putting everything off the 305 onto 350 TBI engine and it working fine, just not getting its full potential.
Member
iTrader: (1)
Joined: Apr 2013
Posts: 372
Likes: 0
From: Ohio
Car: 1987 Trans Am
Engine: 305 TPI
Re: 305 TBI to 350 TBI swap
Very straight forward as dmccain said, at least should change knock sensor, using the right chip made a huge difference in my truck. I used the 305 injectors and chip for a while but was still a dog until I swapped them for 350's
Supreme Member
iTrader: (1)
Joined: Apr 2005
Posts: 1,165
Likes: 1
From: Valdosta, GA
Car: 1991 Trans Am GTA
Engine: L98(5.7 L TPI)
Transmission: 700r4(A4)
Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff
Re: 305 TBI to 350 TBI swap
Out of curiosity, have you considered different fuel injection systems?
Thread
Thread Starter
Forum
Replies
Last Post