2.8 to 5.7 Swap

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Dec 26, 2003 | 10:48 AM
  #1  
hey everyone...been a while since i've been here...so heres the deal...from my favorite most trustworthy junkyard...350 from an 88 GTA...complete with all wiring and computer...also trans...for about 800...here are some questions...i know the v-6 tranny doesn't bolt up...however...are the bellhousings interchangable...because the guy says the tranny is ?...thats my major concern with everything...also...my 3.42 rear end...in good working order...is it suitable...and does driveshaft from the 350 go right into my v-6 tranny and rear end...just some questions that i know the people in this forum can answer...thanx guyz...and for the v-6...will be stored nicely if ever called upon for service again...
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Dec 26, 2003 | 10:55 AM
  #2  
If standard shift, I belive they are interchangable, but I'm not an expert on those. Drive shafts are interchangable from 82-02. Rear gears are suitable, but as most people say, when you start to put serious poer down, upgrade tranny & gears.
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Dec 26, 2003 | 11:01 AM
  #3  
well...i'm not gonna be modding the 350 anytime soon...i have just enough to buy what i need and do this job...but hmm...how bout converting auto to standard shift...could that work...
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Dec 26, 2003 | 11:20 AM
  #4  
No on tranny, splines are different. Unless you can hunt around and find a clutch that is the correct splines, and will bolt to the flywheel. I still wouldnt trust it then, the v8 one does have stronger internals. I belive also different gearing.

Or this is what I found when looking for a tranny on my s10.

Driveshafts swap. Thats why I'm looking for a cheap LS1 driveshaft. I belive the v8's were larger in diameter though.
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Dec 26, 2003 | 01:38 PM
  #5  
ok then...i'm gonna have to take a chance with the junkyard tranny...probably questionable cause they never drove the car...worst that can happen is it needs a new one...but the driveshaft swapping into my current rear end is good...ok...any problems that i may encounter along the way if anyone wants to let me know from now???
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Dec 26, 2003 | 02:13 PM
  #6  
I would say install new motor mounts. Also tranny mount while your at it.

Other then that, I say you need to go to the engine swap board and ask someone who has done it.
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Dec 26, 2003 | 06:31 PM
  #7  
Eh, problems u could find? can't really be sure, but i'd be certain that there will be snags in the road, it's what happens anytime anyone attempts to do anything...the truth is, if something wasn't going wrong, then most likely you didn't do something right, or ur cutting corners.

Neway, transmission rebuilds aren't exactly the most expensive things in the world, especially if the transmission is already seperate from the vehicle. I'd say, buy ur motor tranny combo, take the tranny away from the motor, take it to a reputable shop and 400 bux later you should have a good working v8 transmission, then slide it back onto the engine. Check ur compression on all the cylinders before you start doing the swap, because the last thing you'll want isputting a new engine in and finding out that two of the cylinders deliver zero compression, and find urself having to tear the engine down once it's in the car. Motor mounts are a no brainer, and a low coster so do em, same with the transmission mount. I'd expect the transmission crossmember to be in the same or close to the same location, but i'm alil unsure on that. And ur frame should be predrilled for the v8 motor mounts. Hmmm, what else. Change those front springs, and iron blocked v8 is gonna way a lil' bit more than the iron six did. Guessd you could stick with the manifolds now to save money, headers when u have extra cash, and i'd snag the Y-pipe while ur at it, since i think it's different from the v6 version. Also, make sure the car has a real good reason to be in this junkyard, if a car's fixable (or salvageable) most people will take what they can before sending it to a yard, good engines, good tranny's, seats, etc. See what the people took otu b4, and see what they left, see if the engine is stock, or if some kid tinkered w/ it, and see if the car would really be "totalled" from the accident, or was it just not running good anyway, plus te accident = the total. Get the idea i take it...best of luck, keep us posted.
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Dec 26, 2003 | 06:44 PM
  #8  
well...i am going tomorrow to see if i can hear it run and get a compression test done...they said it was already tested though...but most of the stuff will be done over time...i'll start posting on the swap board but i'll keep an update here...
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Dec 26, 2003 | 07:52 PM
  #9  
If you go with an automagic, try to find as new of one as you can. If you can get the '88, you're alright. Most of the transmission "longevity" mods were done in 1987, and GM did a few more improvements a the years went on. So a 1992 would be better than 1988, 1988 is better than 1986, and ANYTHING is better than the 83-84 era!! (83-84 used weaker 26 spline input shafts, among other problems.)

Er; wait.. 26 spline... isn't that for axles? Damn. I forget the spline difference. But 83-84 did have weaker input shafts than 85-up. In fact if you go after a torque convertor, they'll list 83-84 separate from 85-2003.
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Dec 27, 2003 | 12:35 AM
  #10  
hey tom, if this transmission is the factory unit, wouldn't it be from an 1987+ car anyway? given that the first year for the L98 was in 87 , 86 on some very rare maros if i recall right, but 87 on birds. so, the transmission should be the stronger of the series, but, i'd highly recommend a rebuild, for safety sake (better safe than sorry). Especially since there won't be the labor of removing it, once it's in the car if you drop it at the tranny shop, plus you'd know that atleast one piece of ur puzzle is ready to go, and good (hopefully). good luck.
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Dec 27, 2003 | 12:22 PM
  #11  
ok...so i went today...and talked to the main man there...the tranny is no good...and the driveshaft is also gone...however...complete motor w/ all sensors and computer is present...radiator is present...twin fans are present...coil springs looked good...i'll spend around 400 for everything...good deal or no...also...might i ask what is a cold compression test...
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Dec 28, 2003 | 01:48 AM
  #12  
my understanding of the cold compression test is a test w/ a cold engine. When an engine is cold, things haven't expanded to fill in the extra cracks and creecks, so the engine wouldn't be sealing as well as they would if the block is already hot. Also, if the transmission is bad, it might be a good idea to see if you can nab it for free , just kinda take it off their hands, and to a shop for a rebuild, at bare minimum the shell could be used. I'd say that if you're getting all the wiring (intact) the fans, the radiator, the coils and shocks, plus the motor then ur getting a good deal, so yeh, i'd be more than happy...but still try for some compression numbers.
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Dec 29, 2003 | 12:19 PM
  #13  
I would look into having the entire donor car towed to your house, and simply swap everything over. Don't forget you'll also need the v8 fuel pump, but might as well go new on that. You probably need the v8 tach as the v6 one will not work properly. Swap over any suspension and steering components you can, as the stuff on the GTA will be much better. Check the rear brakes... swappng to rear disc is so worth it. I love the rear discs on my IROC.
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Dec 29, 2003 | 02:17 PM
  #14  
i always thought that the same fuel pump was used for both motors as far as i remember reading...maybe someone can clear that up...also on the tach issue...i would figure as long as a motor is sending a signal to the tach it wouldn't matter...cause when they sell aftermarket ones there is no specification...also...i don't know if he'll let go of the whole car...suspension i'm only gonna upgrade the struts and springs...maybe if the sway bar looks good too because the car is on control arms currently...i'll keep this updated...
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Dec 29, 2003 | 03:48 PM
  #15  
Mike is right, fuel pump IS different. And if your going to get new. A banned agood2.8 stated that the corvette fuel pump flows the same, but is made out of more steel then plastic like the camaro one.

Tach is also "different". On the aftermarket tachs, you have a select switch on the rear, 4,6,8.

If you get your pick on parts, grab the sways too , front and rear. Grab rear coils too as they are different. Rear panhard also needed.
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Dec 30, 2003 | 05:10 AM
  #16  
panhard??
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Dec 30, 2003 | 12:21 PM
  #17  
good luck w/ the swap man...i have a 3.1 and was thinking about a 5.7 swap, but then i started asking questions on here....i decided it'd just be cheaper and much faster to sell the RS and buy an Iroc....anyway, hope you go through with it without too many problems..
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Jan 1, 2004 | 11:46 AM
  #18  
3.42 are not bad gears at all, they are more then do able, so u are fine.
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