Anyone done a manual swap on a 3rd gen F-body?

Hey guys.

I am considering an 88 Trans Am GTA for my fun project car, but I am hesitant because it is an autotragic. Of course, these only came in autotragic, but whatever (thanks GM). Anyway, has anyone here done a manual swap on one? If I can get the swap done for around 1k - 1.5k, it would be totally worth it. I will eventually peruse the f-body forums out there, but I trust you guys more.

Please learn me, O Great Hive Mind of All Things Automotive.

Internet lore is that GM never put the WC T5 5 speed in the 350 third gen F bodies because they feared they would have to warranty too many transmissions. The rear suspension torque arm mounts to the trans tail so you'll have to deal with that with any non factory transmission. The easiest manual swap is probably an aftermarket shifter and a shift kit for the 700R4, combine that with a good rebuild and you'll have a transmission that you can beat on without worrying too much.

There are kits out there to attach the torque arm mount to the chassis instead of the transmission. That would open up the transmission choices. T5 is questionable behind a 350 strength wise, might want to consider going with a newer trans like a T56. Sure it will cost more, but will be much better in the long run. Ah heck, might as well swap a LS/T56 combo, its only money.

I've seen T5s last behind 350s with a good positive stop shifter and minimal clutch dumping.

From what I can tell, the 3rd gen F-body T5s are fairly hard to find and have several goofy differences in them, like the torque arm mount and the bell housing being designed to rotate the whole trans over a few degrees compared to a Ford T5. Real early cars used a T10 but again only behind 305s. If you are keeping the L98 the most common swap is an LT1 T56. SLP also put Corvette ZF 6 speeds behind L98s in the '92 Firehawks, so that option exists if you get lucky finding one of those. Or there's the TKO500/600 if you want to throw money at the problem. (or get lucky finding a used one)

Here's the stickied 700R4-T56 Swap thread on ThirdGen.Org.

My understanding is that the T56 fits onto the 700R4 mount on the stock crossmember, and some people seem to get lucky and the stock driveshaft fits too. Then it's just a matter of cutting a hole in the floor for the shifter and making the clutch work. T56 shifter is a couple inches further back compared to a T5.

Never done the swap but I read about it a lot when I had my '86 Firebird.

Chadeux wrote: From what I can tell, the 3rd gen F-body T5s are fairly hard to find and have several goofy differences in them, like the torque arm mount and the bell housing being designed to rotate the whole trans over a few degrees

Also I currently have a third gen F Body T5 for sale in Michigan

The T56 was configured to be a direct swap for the 4L60 family. Impala SS guys do it all the time and even use the same driveshaft.

Using a T56 is not just that easy though. The 700r4 has a 3.06 first and .70 OD. The majority of T56s use a 2.66/.50 gearset. That doesn't look like much on paper, but its pretty huge. Let's say you have 3.08s in the rear now. In order to keep the same basic gear spread, you'd have to switch to 3.73 or 4.10 to keep things the same. 4.10s would keep the same highway RPM and give you a touch shallower first. 3.73s will lower highway RPMs and keep a similar first. That .50 double OD even makes 4.56s act like 2.25s on the highway

Also note that if you do a gear swap, you won't stay with the current driveshaft. The .50 OD spins the shaft at twice the speed of RPM, and a stock driveshaft will sing. Strongly suggest getting a good aluminum shaft that is balanced at the highest RPM the shop will do.

All GM T56s have the bosses for the torque arm, and should be mostly a bolt-in for a 700r4. There will be trans tunnel massaging. (hammering). The reverse lockout solenoid can be eliminated and plugged, as can the skip shift solenoid, but there are some bumps on the case that will hit.

Ok, thanks guys. That sounds like more than what I want to tackle right now. I'll keep looking.

When I did mine, I had a donor car so all the bits were right at hand. A World Class T5 with some work could hold a stock 350 with care, but buy the time you spend that much you could just go the T56 route. (and the T56 is easier to find these days)

Which rear diff do you have? A 350 car in 1988 most likely has the 9 bolt Borg Warner with 2.77 gears. These rears can be changed to 3.45 or 3.70 gears and are very durable. LT1/LS1 6-speeds had 3.42 gears so you can chose from there.

thirdgen.org is a really great knowlege source.

Should you need it I have a clutch brake pedal setup I'd be willing to let go inexpensively.

I've got a manual 4th gen parts car, not sure what all crosses over but if you need clutch hydraulics, aluminum driveshaft, pedals, ect I wouldn't ask much for them