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Vortec 350 Swap

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Old Jul 18, 2009 | 09:06 PM
  #1  
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From: Philadelphia
Car: 1988 Trans Am
Engine: 5.0 TPI
Transmission: TH700R4
Axle/Gears: 3.43 posi
Vortec 350 Swap

I'm trying to come up with a game plan to replace my tired 200k+ 305tpi that's in my 88 trans am. I've been doing a lot of reading on swapping a vortec 350 and would like to make sure I understand it correctly. To successfully swap the motor I will need:

  • a 96 or later vortec 350 motor
  • An TPI/Vortec intake baseplate
  • bigger injectors
  • PROM from a 350
Is that accurate or did I miss anything? is there any particular block to look for or to stay away from? Can I use it's stock cam or should that be changed right away? (I've read a lot of people recomend the LT1 cam) Computer wise does it need anything more then a new PROM? The car has MAF and from what i read that's more forgiving w/ mods. The car is not a daily driver and I would most likely build this as I can afford it. I'd like to stay stock with the intake right now and upgrade that in the future. Any suggestions?


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Old Jul 20, 2009 | 10:37 PM
  #2  
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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
You don't absolutely have to have the 350 PROM, but you should use a 350 knock sensor and module.

If you aren't upgrading the intake, then leave the stock cam in the engine.

The Gen I Vortecs only lasted a few years, 1996-1999 in light trucks, and some heavy trucks into 2000. After that, they were the LS-style blocks.
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Old Jul 21, 2009 | 04:18 PM
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mmm88TA's Avatar
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From: Philadelphia
Car: 1988 Trans Am
Engine: 5.0 TPI
Transmission: TH700R4
Axle/Gears: 3.43 posi
Re: Vortec 350 Swap

thanks, after more reading I saw the difference in the later "vortec" engines and how GM uses the term rather loosely. Is it better to try to get a whole vortec motor (vortec's have the plastic timing chain covers and the ERG is set up different any other major differences?) or just a 86 and later block and vortec heads? I'm not sure what combos will work other then what I've read on TGO. This is all in the planning stage right now the 305 is showing its age but still runs well enough for cruising on the weekends, it had been my daily driver for about 7 years and now that it isn't I'd like to be able to play around with it.
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Old Jul 21, 2009 | 04:31 PM
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five7kid's Avatar
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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
The '96-'99 Vortec swap is a sound concept. The heads are pretty decent.

I'd say '87-up rather than '86-up. '86 didn't have roller lifters.
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Old Jul 21, 2009 | 06:01 PM
  #5  
mmm88TA's Avatar
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From: Philadelphia
Car: 1988 Trans Am
Engine: 5.0 TPI
Transmission: TH700R4
Axle/Gears: 3.43 posi
Re: Vortec 350 Swap

Gotcha thanks for the info. I'll keep doing some homework before I start anything. This will be my first attempt at any engine work, I've done general maintenance stuff to the car but nothing major.
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