Has anybody done it? I'm planning to build a fairly stout 383 for my 86 SE (it'll be a fastback soon), and want to be sure I have a drivetrain that will take whatever I throw at it. I'm not too worried about the electronic aspect of the swap, mainly just how much modification was needed to get it in and what had to be done as far as axles (custom length I'm sure...sources??). Also, is there a preferred donor vehicle for this trans? Thanks a lot!

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86 Fiero SE

I'm interested also.

Bump

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Finally the carbed, camed, 350 is in the 88GT and deafening people on a regular basis.
Please E-mail me at Wicked88GT@yahoo.com

I don't think that anyone has done this yet. This transmission would require a controller that would probably cost more than $1k, are you willing to pay that much?

I have a 383 bolted to a 4T65Ehd and I have a 4T80E to compare. The standard V8 adapter needs to be slightly modified on the bottom corner where it interferes with the trans case, and for the 4T80E it would be a more severe cut and require another threaded hole. You will also need to cut a nice big chunk off the engine block where the starter originally mounted on the Chevy. The 4T65Ehd was recommended because of the availability of upgrade parts and a Torsen limited slip diff, and lack thereof for the 80. The 4T80E is only rated 25 lb/ft over the 65. The 80 is 100 lbs heavier without exaggeration. For an 80 you would use Cadillac shafts shortened approx 3/4" on each side, and swap the outer CVs for Manual Fiero parts using the Cadillac ball races. The Fiero cradle needs a bit of clearancing along the rear crossmember for the 4T80E. The shift controller was well over $1000, but is completely tunable and can be used from full auto to full manual with pushbutton shift, or anywhere in between, and I believe it can be configured for either trans.

Because of the physical size, added weight, and lack of upgradability of the 4T80E, I think the 4T65Ehd is a better choice. If I get a chance I'll take a picture of a 65 next to an 80. I do have a 2k mile 4T80E for sale if you're interested.

quote Originally posted by rockcrawl: Because of the physical size, added weight, and lack of upgradability of the 4T80E, I think the 4T65Ehd is a better choice. If I get a chance I'll take a picture of a 65 next to an 80. I do have a 2k mile 4T80E for sale if you're interested.

I would agree - except if you really are going "all out" with HP. The 80e weighs 100lbs more for a reason... it was made to haul around heavy cadillacs with 300hp engines. I think in a fiero, you could easily push 400-500hp with no problems stock. The 65e would need some go fast parts to handle that with some error margin.. BUT - on the other hand, it IS 100lbs lighter, AND has less drivetrain loss. IIRC the 80e is around 25% and the 65e is around 20%. That's free hp and free weight reduction. But you pay with upgraded parts.

How much does the 4T65E weigh? If its easily upgradable, and only 25lb/ft weaker in stock form, sound like it might be the way to go. BTW does it share torque convertors with the 4L60E, like the 4L60E does with the 4L65E? Most of my transmission knowledge is with the RWD style transmissions. I don't really have a problem with running one of the electronic controllers (always wanted paddle shifters, and this is now an easy, though not cheap, mod). I do want a transmission that could be built to handle some fairly agressive driving, and better aftermarket support would sway my decision. I'm known for going "overkill" on drivetrain parts, but I'd much rather do something once and not have to worry about it again.
Also, what is a good donor vehicle for the 4T65E (better valve bodies in a GTP possibly, for example?) ?

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86 Fiero SE

The 4t65e is about 200lbs, and the 4T80e is about 300lbs. I would definitely recommend the 4T65e. It's been hotrodded by the 3800SC community for a while and can be built to handle much more power than a stock 4T80e. Sure, the 80 can be built, but there isn't really an aftermarket for it.

The weights are 196 pounds and 296 pounds. I don't know which converters interchange among the transverse units, but they are different than the rear wheel drive ones. The 4T65E should be an HD version from one of the supercharged 3800 cars, beyond that I don't know what differences there may be besides gear ratios. Look into some of the 3800 performance sites to find out what can be done to the 4T65E.

...the 65-e (even modded) can handle power but not as much as an 80-e (stock)...period!
With all the "go fast parts" it is shear luck that the 65-e still surpasses a 60-e (in the ability to hold power)...seriously!
While it is true there is hardly any performance parts for the 80-e...what else would you need? you can get a tq converter and pick a tranny with 3.73 FDR...call it a day! IMHO, the one and perhaps only negative thing is the weight!!

Are there anty decent upgrades for the late 4T60 (1991).??

I too am doing a SBC swap but I'm hesitent about using the 4T60. I know with 4t60-E and 4T65-E have progressively gotten stronger but I've always been curious about the older 4T60 and a SBC in the 325-350HP range.

http://kitcarmag.com/featuredvehicles/5644/

The transmissions show two torque ratings a max engine torque and a max gearbox torque. I suspect the max engine torque is in reference to the max output of the engine(s) it is mated to and the max gearbox torque is the actual maximum rated handling capacity. I noted one GM application where the maximum engine torque exceeded the max engine torque listed for the transmission that it was mated to by about 5-10 points above 435, however the max gearbox torque was over 630 Lb/ft. If that is correct then the max torque capacity of the 4T80 is 60 lb/ft greater than the 4T65HD. I've worked on enough cars to know that I want dependability. I would definately opt for strength in this area, even if I'm incorrect and the difference is only 25 Lb/ft. You can always crank up the power to compensate for the additional 100 lbs. It's actually not that much given that some of us owners differ in weight by that amount.