Im a fairly young corvette owner/car guy and im looking to do some pretty fun stuff with my 85. my plan is to somehow make this thing manual. off of just pondering the idea i was thinking i would just buy a brand new/aftermarket transmission whatever that pertains. and i would essentially plug and play. but im not sure of all the ins and outs of transmissions and what i would need to install change or even need to make this completely feasible. i know its not going to be a cheap job what so ever but i am looking to what i would need/what would be best.

 

The two main options you have are the Tremec TKX and the ZF 6-speed.

Tremec: These are sold as a kit for corvette manual conversions, usually called something like "Perfect Fit" or similar, from various sources. They will be upwards of $3500 depending on where you get it and what options you choose. I've heard various stories about how easy or difficult the install is, so it's probably worth not getting the cheapest one you can find. But also, I think they usually advertise them as a manual-to-manual conversion (Doug Nash 4+3 to normal 5-speed), so do some research and make sure this will work on an auto. You might need to change your C-beam and drive shaft too, which ever way you go.

ZF: Probably a much cheaper way to convert to manual, but will also probably take a lot more tinkering and adaptation. This is the transmission that later manual C4s came with. Since your car is auto, you will have to modify the center tunnel to accept the manual no matter which transmission you choose. This sounds a bit daunting to me, but I haven't done it, so get advice from someone who has. A lot of people will sell complete ZF conversion kits that include a tunnel section that you have to install. But the risk with the ZF is that it won't be new, so you have to make sure you're getting one in good shape, unless you're okay with rebuilding it.

All in all, this will be a big project, and which route is best will depend on whether simplicity or cost is more important to you. Good luck!

Edit: One more thing I forgot to mention about the ZF, it's designed for the LT1 engine, so you will need an adaptor flywheel. They are readily available from Fidanza, but they aren't cheap, so that will neutralize some of the cost advantage of the ZF.