I have an 84 Fiero with a V8 LT1 with a manual transmission. I want to swap it for an automatic. Which kind would be the easiest to install? And that would make a good fitment match. Thank you.
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10:35 PM
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Dennis LaGrua Member
Posts: 15854 From: Hillsborough, NJ U.S.A. Registered: May 2000
Send a PM to V8Archie. He's the resident SBC swap expert. He will know.
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11:16 PM
Feb 9th, 2013
rogergarrison Member
Posts: 49601 From: A Western Caribbean Island/ Columbus, Ohio Registered: Apr 99
Depending on your engine management the 4 speed used with the cadi 4.9L will be the first on the list up from the 3 speed. I was considering going automatic with my V8 swap and was told by a builder that strengthened the 700 R4 in my camaro that the cadillac tranny had some improvements after the first year as usual. I believe it is or certain years were fully electronic but the parts were interchangeable for the most part with the TCC only 4 speeds found behind the 3.8L so you could have one of those built to withstand 4.9L torque levels plus a little more. Beyond that you'll need ECM management of the later and stronger autos.
You may also have the challenge of your adaptor plate limitation if it is not rotated for the engine to clear the auto.
[This message has been edited by Joseph Upson (edited 02-09-2013).]
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10:47 AM
Carcollector Junior Member
Posts: 8 From: Monterrey, Mexico Registered: Jan 2013
The old non "-E" tran's are the easy ones. The newer 4t60-e , 4t65e and 4t65 HD are all computer controled. My son does his 4t60-E with switchs, no trans controler. That you need to think about the gear and the torque converter speed.
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12:01 AM
FFIEROFRED Member
Posts: 751 From: GULFPORT, MS Registered: May 2008
I did he overdrive auto many years ago. I had archie make me a CV axle for the drivers side because i couldn't find a stock one that was short enough. I had to cut the cradle away on the drivers side to keep the engine out of the pass side frame rail. It was a lot of work. But it was the biggest improvment ( other than the V8 ) that i ever did to the car. The first time my budy road in it after the trans install he said " this is just like a F'in Buick" because of the low rpm cruze, and the low noise. the caddie 4.9 has a very low stall speed. the 3800's, not as low. the 2.8/3.1 have a 2060 rpm stall ( high for a stock sbc ) . 4.9 caddie's have a tall gear, 3800 = tall to middle, 2.8 / 3.1 ( in a "W" car ) have 3.29 / 3.33.
I have a comp cam roller cam. I use a 3.29 gear / "FJ" converter ( 2060) stall, 4T60-E. Hit it from idle, fry the tires, any size / type tire. It will sit at a stop in gear with no creep. Feels like a slipping trans a little at low speeds. But when you want to go, it's gone. The 4T60-E is longer on the pass side than the 4T60/4T40.
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07:06 AM
Archie Member
Posts: 9436 From: Las Vegas, NV Registered: Dec 1999
Everything that FFIEROFRED said plus, you have to take this into consideration.
On the LT1 & LT4 only, because of the Ignition system & the unique Harmonic Balancer on the LT engines, on a stick shift Fiero with an LT1, you have to move the Engine/transmission assembly 2-3/8" to the left in the car. With an LT engine & an automatic, you have to move it to the left 1.9".
FFIEROFRED has a normal SBC in his car. So consider that the amount of cutting he had to do to fit a 4 speed OD trans will have to be increased because of the larger size of the transmisssion bottom pan & side cover & the fact that you'll be moving the trans. 1+" farther to the left that he did.
Switching from a Stick shift to an automatic will also require my automatic adapter plate & flexplate setup.
Archie
[This message has been edited by Archie (edited 02-11-2013).]
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11:44 AM
Feb 12th, 2013
Carcollector Junior Member
Posts: 8 From: Monterrey, Mexico Registered: Jan 2013
