I am new to the Fiero world. I recently purchased a 1985 GT. My intent is to install a V8 in place of the 2.8L V6 automatic. I found a TH440 out of a 1989 Pontiac Bonneville. Will this transmission handle the torque of a sbc? I would like to stick to an automatic trasmission as I am too tall to shift a manual comfortably in this car. And my plan is to also use a carburated engine in order to eliminate the computer. This may be a little old school but it makes it easier in my mind to work on.

Hey there,

The 440T4 will certainly work as long as you are not "extremely heavy" on the foot. It's only rated for about 235lbs/ft of torque which is a bit better than the TH-125 - 200lb/ft rating. It's a pretty strong trans but won't take a ton of abuse. Search 4T60 and 440T4 for some info. Since most of those early ones have a vac modulator etc, they work well with a good old carbed V8 (and nothing wrong with a carbed v8 either...)

You can also try IPT in NJ for some Hi-perf parts for the 4T60/440T4 (The 440T4/4T60 is the same by the way), GM made a mod in the designations for the trans at some point. Some parts for the -E trans (4T60-E, 65-E, 80-E and the GM F-7 which is kind of a beefed up 4T80 only found in the Caddy Allante) may interchange and they do have different valve bodies / shift kits for the 4T60/440T4's as well. IPT can tell you how to beef up the trans if you want to go a bit more crazy with the SBC.

You could also try paddle shifting a 4T65-E or 4T80-E like others have discussed but I'm not really not familiar with the feasibility of that. (Not really into paddle shifting...seems a bit annoying to me)..

Try here:

http://www.importperformanc....com/gmautofwd.shtml

Also try here for the torque info:

http://www.gnttype.org/tech...sion/transtutor.html


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I'm not driving too fast, . . . I'm flying too low.

[This message has been edited by 3084me (edited 01-09-2008).]

My Build Thread (see link in the signature) has some details of the 4T60 I had rebuilt to use with my LT1 swap - so far it's holding up well.

Ryan

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1986 Fiero2m8 (LT1 NX / 4T60 Roadster Build)
https://www.fiero.nl/forum/Forum2/HTML/071642.html

There a several good threads about the swap. You will need a new fuid tube, selector switch, VSS gear from your TH-125, Vacuum modulator and a vacuum source, a TCC set-up, modified rear mount holes, a custom shift cable bracket, and the axles from a 1987 Grand am with light brakes for starters.

Just do a search under 4T60 or TH440