need help swapping 5.0 for 5.7 1990
Member
Joined: Jul 2010
Posts: 258
Likes: 0
From: Niagara falls,ontario
Car: 84 firebird
Engine: 355
Transmission: 700r4 stage 2 shift kit 2500 stall
Axle/Gears: 3.42 posi
Re: need help swapping 5.0 for 5.7 1990
we need more info about the engine is it 100% complete or not? if not just take the stuff off the 305 and put it on the 350 and im assuming it is fuel injected (tpi) so you'll have to change the eprom in the passenger fender to the 350 5.7l one
Senior Member
Joined: Feb 2010
Posts: 1,125
Likes: 1
From: San Diego, California
Car: Trailblazer EXT 4.2 (Firebird Form)
Engine: 5.1 4bbl
Transmission: 700R4 Mega Raptor Level 4
Axle/Gears: 2.73
Re: need help swapping 5.0 for 5.7 1990
We need to know where you will be registering your car, is there emissions testing? we do indeed need more info... we need to know what fuel delivery system you'll be using... are you going with carb, TBI, or TPI...
Re: need help swapping 5.0 for 5.7 1990
yes engine is complete minus the alternator. Some people are telling me i have to do some rewiring. Would switching the eprom elimanate the rewiring. my engine was carb new engine tpi
Member
Joined: Jul 2010
Posts: 258
Likes: 0
From: Niagara falls,ontario
Car: 84 firebird
Engine: 355
Transmission: 700r4 stage 2 shift kit 2500 stall
Axle/Gears: 3.42 posi
Re: need help swapping 5.0 for 5.7 1990
are you sure it was carb? or was it tbi they look similiar because im pretty sure in 1990 they didnt come carb'd unless somone already changed it around, if so your going to need a whole harness plus computer (if carb'd it didnt come with a cmputer) or you can just go carb'd to carb'd or tbi to tbi or tpi to tpi whatever your case may be, but i think we need some pics to see what it really is and what wiring you do have
Supreme Member
iTrader: (4)
Joined: Mar 2009
Posts: 3,079
Likes: 4
From: Pepperell, MA
Car: 1987 Trans Am
Engine: LQ9/L92
Transmission: 4L60E
Re: need help swapping 5.0 for 5.7 1990
wiring will be a necessity, so grab the harness and computer that's with the motor you're grabbing. california is very strict on engine swaps, so you need to make sure you have all the necessary emissions equipment for the motor you're looking to install
Trending Topics
Senior Member
Joined: Feb 2010
Posts: 1,125
Likes: 1
From: San Diego, California
Car: Trailblazer EXT 4.2 (Firebird Form)
Engine: 5.1 4bbl
Transmission: 700R4 Mega Raptor Level 4
Axle/Gears: 2.73
Re: need help swapping 5.0 for 5.7 1990
are you sure it was carb? or was it tbi they look similiar because im pretty sure in 1990 they didnt come carb'd unless somone already changed it around, if so your going to need a whole harness plus computer (if carb'd it didnt come with a cmputer) or you can just go carb'd to carb'd or tbi to tbi or tpi to tpi whatever your case may be, but i think we need some pics to see what it really is and what wiring you do have
To OP, you will have to get your wiring harness off the TPI engine and install it accordingly, the Carb'ed engines that came from GM I do believe all had ECM, not sure at what point the carb became part of the emissions and required it to be controlled electronically... ... regardless here in California you will have to take it to a ref and have it certified, you might be able to get away with just taking your car in for smog if the technician is an idiot and doesn't know what he/she is looking at... not sure if the VIN when they scan it into their system brings up that it's a TBI.... but as far as I know I think you do have to take it to a ref, the ref will basically check all of the emission components to verify that they are in their respective location as was when they left the factory floor... also... if you have Carb, you can only go up to TBI or TPI, so if you have TBI, you can only go to TPI and not go back to Carb, at least that's the case here in California... good luck...
Supreme Member
iTrader: (4)
Joined: Mar 2009
Posts: 3,079
Likes: 4
From: Pepperell, MA
Car: 1987 Trans Am
Engine: LQ9/L92
Transmission: 4L60E
Re: need help swapping 5.0 for 5.7 1990
you're in luck, its just going to be more labor and money intensive than most have to deal with. The years are correct and both motors are car motors (CA won't let you put a truck motor into a car). As mentioned before, you'll need all the wiring, ecm, and emissions stuff that came with the tpi motor. you'll also need to go to a tpi pump (but that's not a hard ordeal). You may also have to rewire the stuff under the dash (get yourself a Helms manual, its a lifesaver). When performing a motor swap in CA, you have to get a special inspection done to certify the swap was done correctly, or else you may not be able to get through future yearly inspections
Senior Member
Joined: Feb 2010
Posts: 1,125
Likes: 1
From: San Diego, California
Car: Trailblazer EXT 4.2 (Firebird Form)
Engine: 5.1 4bbl
Transmission: 700R4 Mega Raptor Level 4
Axle/Gears: 2.73
Re: need help swapping 5.0 for 5.7 1990
Member
Joined: Jul 2010
Posts: 258
Likes: 0
From: Niagara falls,ontario
Car: 84 firebird
Engine: 355
Transmission: 700r4 stage 2 shift kit 2500 stall
Axle/Gears: 3.42 posi
Re: need help swapping 5.0 for 5.7 1990
you could just go 350 tbi...change the computer not have to change the wiring and you can use everything else off the then u dont have to go through the pump wiring etc. this is why i love carb'd...soooo much easier, for me anyways lol
Joined: Mar 2000
Posts: 43,187
Likes: 46
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Thread
Thread Starter
Forum
Replies
Last Post
Dialed_In
Firebirds for Sale
2
Aug 20, 2015 01:45 PM






