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305 tbi - 5.7 tpi swap?

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Old 06-27-2011, 01:02 PM
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Car: 87 Trans Am
Engine: 350 carb'd
Transmission: 700R4
Axle/Gears: Stock
305 tbi - 5.7 tpi swap?

Hey everyone, I recently found an 87 trans am with a 5.7L TPI motor in it, was wondering if I should just grab that up and swap motors. It looks to be in goof condition n I figured I could pull it out n rebuild it then just swap it into mine. Would that be a good idea or should I just save up for an ls1 or lt1. What would be the HP gains from going from 305 tbi to 350 TPI? The trans am I'm looking at only costs 700 bucks and it has decent black rims and the rest of the ground effects that I'm missing. Let me know what you guys think. Thanks.

Here's the link to it http://phoenix.craigslist.org/evl/cto/2457064948.html
Old 06-27-2011, 02:35 PM
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Re: 305 tbi - 5.7 tpi swap?

the tpi 350 is rated at like 240 HP isnt it? the L03 is rated at 170. it'd be a nice increase in power. You can also soup up the 350 with some heads, and cam, and intake changes and make more power. you'll need to transfer all the wiring harness, change the fuel pump and im sure a few more things I dont even know.
Old 06-27-2011, 04:01 PM
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Car: 87 Trans Am
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Re: 305 tbi - 5.7 tpi swap?

Fuel pump? Really? Just put a new mallory fuel pump in today, and it is amazing! Il need new tires to keep up with this thing, before, I couldn't peel out much at all, now it just ROASTS em. It's definitely a good buy
Old 06-27-2011, 04:06 PM
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Re: 305 tbi - 5.7 tpi swap?

You can either swap the harness, or repin the ecm connectors....search for "repinning tbi to tpi"....which is a better option, in my opinion. If youve got the scratch, go ahead and buy the whole car for a parts car.
Old 06-27-2011, 09:30 PM
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Re: 305 tbi - 5.7 tpi swap?

Originally Posted by Matt1821
Fuel pump? Really? Just put a new mallory fuel pump in today, and it is amazing! Il need new tires to keep up with this thing, before, I couldn't peel out much at all, now it just ROASTS em. It's definitely a good buy
oh well if it enough psi to feed a TPI setup then you dont need to change the fuel pump
Old 06-28-2011, 02:49 AM
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Car: 87 Trans Am
Engine: 350 carb'd
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Re: 305 tbi - 5.7 tpi swap?

Il definitely look into re-pinning, but I was wondering, would I need different motor mounts or trans. Or anything like that? I'm sure I could use the tranny from the donor car, looks to be in decent shape, a good rebuild and I should be in good shape, maybe bore it out while its already apart, who knows... I'm gettin excited just thinkin about it... Il make a thread of the swap with a ton of pics.

Last edited by Matt1821; 06-28-2011 at 03:57 AM.
Old 06-28-2011, 05:40 AM
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Car: 87 Trans Am
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Re: 305 tbi - 5.7 tpi swap?

Also, I do have a couple questions, I've read plenty of threads on this topic and don't understand why I would need to repin anything or get a painless harness? What's wrong with the ecm and harness in the donor car? It won't be just a straight across swap? Why?
Old 06-28-2011, 04:24 PM
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Re: 305 tbi - 5.7 tpi swap?

You can use the harness from the other car....but have you ever tried to pull a harness intact from one of these? PITA. Im only saying "repin" it because you can spend an hour and a half doing that or 2 or 3 days running a new harness.
Old 06-28-2011, 11:17 PM
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Re: 305 tbi - 5.7 tpi swap?

I just got done pulling a buddies 350 tpi out of his donor car and between the 4 of us it took us about 4.5 hours to do, but that was with a lot of smoke and beer drinks. What we did was just disconnect the wiring from the inside fendors then pull the motor and tranny up then pushed the car out and set the engine/tranny on a couple wooden blocks. Then we started in on pulling the wiring harness off and then completly disassembling the engine. That whole disassembly maybe took an hour. In short just pull the new engine and leave the wiring pilled on top the engine, drop it into your car and then start hooking everything up.
Old 11-14-2012, 10:19 PM
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Re: 305 tbi - 5.7 tpi swap?

did you ever complete your swap?
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