Ruud W

Hello team members,

Can anyone tell my what transmission to put on a Buick 300 cid. Now it has an ST300 on it, but it no longer works. Which is the substitute without applying any adjustments. Some say that a TH350 or 400 can do without problems. Even a power glide. But I doubt. The engine has been completely overhauled. Now I want to put a good and reliable transmission behind it. It's a 1965 Buick Special 4-door


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A BOP TH 350 fits in place of a ST 300 using your current mounts and driveshaft. You will need to make the linkage work.

A BOP ST or TH 400 will bolt up, but the crossmember needs to move back, the mount needs to be modified or a 400 mount used, the driveshaft needs to be shortened, a different yoke is needed and you will need to sort out the shifter linkage.

A BOP TH 200 4R (4 speed overdrive) will fit in place of the ST 300 and use your current driveshaft, but will require a different crossmember (or heavy fabrication related to the current crossmember and mounting) and will require you to sort out the shifter linkage to make it work.

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Why not just have the ST300 rebuilt??? They ARE a reliable trans. Like said a TH350 is just about a bolt-in swap. AND as far as the linkage, again is no problem as you will more then likely be able to pull it down to 1st. gear with the play that's in the linkage. IF you don't like it the way it is there are available options for the shifter in a variety of diff. places AND it will feel like the little 300V-8 will feel like it gained a 100HP because of the much LOWER 1st. gear ratio.

Tom T.

Ruud W

Thanks Steve and Tom for the answers I have certainly been helped. Because I live in the Netherlands and the supply of second hand materials is very scarce, I will have to be very sure with what I can find as an alternative. But for now I think I'll have the ST300 overhauled. With the purchase of another transmission, not knowing if it is good, and the adjustments I have to make, I think the cost will be lower with a complete overhaul. And the car remains as it is, ex factory.

Thanks again.

Ruud Willems