I have an 86 fiero with a v6 and a 4 speed trans. I want to change it to a 5 speed and eventually install a supercharged 3.8 or 3800. Are all the engine and trans cradles the same? and what would be the best 5 speed trans to install as I am sure that there is others that will fit, than just ones out of a fiero. I am looking for ease of installation as well as affordibility.
5 speed trans
- Thread starter jacob951
- Start date
SGPHIREWIRE
New member
I know all the fieros match up to the 3800 and even the 3.8 except automatic because it cant handle the torque. But almost any GM should match nicely. ( Fiero Engines, and Tranmissions are cheap though.
The 5-spd getreg used in the late 86 thru 1988 is the easiest and least expensive to swap. Bolts right in. Just need shifter assembly, slave cylinder, and shift cables.
The G6 6-speed will fit but requires some minor mods and the cost of the trans is high due to limited availability.
The G6 6-speed will fit but requires some minor mods and the cost of the trans is high due to limited availability.
cradle
Thanks for the advice about the trans. How about the cradle? Are they all the same or are there different ones for different years, engines and trans? I have been thinking of just buying a new one and building it with the new engine and trans while I an still driving the car. Then when it comes to installation hopefully it will be easier.
Thanks for the advice about the trans. How about the cradle? Are they all the same or are there different ones for different years, engines and trans? I have been thinking of just buying a new one and building it with the new engine and trans while I an still driving the car. Then when it comes to installation hopefully it will be easier.
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The cradles from 1985 thru 1987 are the exact same. 1984 just needs 2 holes drilled to fit the small shock strut used on the V-6's. 1988's has different suspension points and slightly different mounting points.
I would NOT recommend the isuzu with use of a v8 period. They have been known to break behind the stock 2.8 v6.
Here is a vid of a guy breaking his 3rd isuzu trans behind his v8.
IMO the v8 isn't worth it.
http://www.youtube.com/watch?v=h4_EuqCVWFo
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Please read what I posted. The Isuzu has been used with V-8's with LESS than 250 hp with no problems. I then stated I would NOT recommend it if you are going over 300hp. I know of a LM1 V8 Fiero that is using an Isuzu 5-speed and has been running fine for nearly 10 years now. The LM1 is only 190 hp.
The video you posted shows a 350 hp ramjet. Of course a 100 hp more horsepower is going to stress the transaxle more.
Finally the movement he is getting is most likely he used the rubber mounts for the cradle. If the cradle is flexing that much it will also cause problems.
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Zimgxp
New member
V8's will work. You just have to be smarter than the transmission.
Like I have said, the stock 140 hp v6 has broken the isuzu when driven slightly harder then your grandma would drive it. I guess if you are shifting it at 2500 rpm and 10% throttle the isuzu could hold a 500 hp engine. But then whats the point of having all that power if you can't use it?
To the OP, Don't use the isuzu with the 3800. You are asking for trouble and there is a reason GM only mated that trans to 4 cylinders.