You can make it work, but I want this thread to give you some insight and to let you know what you are up against.
Centerforce makes a steel flywheel for a Buick V6, but install will require rebalancing of the rotating assembly as the balance was off as it came out of the box.
I used a McCleod scatter shield which has dual bolt patterns on the back side where the gear box bolts. My application used a Saginaw 4 speed (dont try this as they EXPLODE) which is the same as a Muncie, GM BW T10 and GM BW T5. It also has the bolt pattern for a Ford Top Loader which is the same as a Tremec TKO.
The scatter shield was also almost $400 and the flywheel was $350 + labor to disassembled/reassemble and rebalance the engine. If you want to save some cash and are using a GM gear box NOT a Tremec, you can use a GM aluminum bellhousing from any 66-81 BOP manual trans car. There is another issue with any of these which I will explain later. You can use a GM 10.4" diaphram clutch (that is the biggest you will fit on the small Buick flywheel. Trans crossmember modifications as needed. If using a GM Muncie 4 speed or T10 you can use a G body crossmember from ANY of the 78-88 models with a 3 speed automatic. You can also use the stock GM driveshaft. Yoke would depend on what gearbox you use since the GM trannies can have a 27 or 32 spline. A Tremec TKO uses a 31 spline Ford C6 yoke and would require modifications to the driveshaft.
As for clutch actuation, you can buy the pedals from Muscle Cars only in Pennsylvania. The next issue is you will have to fabricate a clutch linkage to get from the pedal to the fork. The only mechanical linkage available is for small block Chevrolets. John Bzdell over at
Monte Carlo SS Information & Resources devised a hydraulic set up using 3rd gen F body hydraulics. What you could do is use the F body master and run it to a Tilton hydraulic throwout bearing assembly which replaces the front bearing retainer on the front of the gear box. As the next issue you will have will be getting a standard GM clutch fork to clear the floor pan. When GM installed a manual transmission in the 78-81 model A/G bodies they had a special fork AND a special mounting of the fork pivot stud to effectively lower the point on the fork where the pushrod from the z bar would contact it. Luckily Buick V6's were available with 3 and 4 speed manual, although finding this bell housing is difficult since not many were made. The fork though is still available from GM and Muscle Cars only.
What you would have to do if using a scatter shielf or a non G body bell is you will have to clearance (read that as bash) the floor in under the gas pedal since there is not enough room for the fork to swing.
You might have to eliminate the console depending on where the shifter comes up. The 4 speed gear boxes come up off center of the centerline of the tranny tunnel and mount pretty far back. The Tremec comes up in the center and mounts very far back, but for less than $300, they have a mid shift conversion that would put the shifter in the same general area as the G body manual transmission.
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Still interested in doing the swap?
I have put together spread sheets of how much it would cost start to finish a swap like this and you are easily past $1000 without a gear box. Add in the cost of a new Tremec (approx $1400-$1700) and you can see it is very expensive. You could built a th400 or even a pretty strong 2004r for less.
Not trying to sway you. I had put a manual trans behind a Buick V6 before and have had manual transmission G bodies. I know whats involved. Ask if you have questions.
Thanks,
Lee Josephs