I have a '73 convertible with the L-48 TH400. I've been doing some research and reading a ton of posts over the last few days. I'm wondering if anyone has a complete write up on doing the auto to 4 speed conversion including the changes I'll need to do to my wiring. I'm trying to make the car as stock as possible keeping all the seat belt warning, reverse lights, and neutral safety switch that would have come on the car if it was original. I have a line on a '76 L-48 4-speed car where the owner will sell me all the parts needed to do the conversion. Based on my research I believe the 76 came with the BW T-10 trans versus the Muncie in a 73. Here are a couple things I've come across so far.

1. Does the 350 crank requiring drilling for pilot bearing. Seems like if it is a pre 1986 crank the answer is no.

2. Does the floor need to be modified. Since it's a '73 with the fiberglass floor the answer seems to be no.

3. Do I need to modify the cross member. Here I've seen multiple answers. Some have said yes, others say no. Some say you need to add a shifter bracket, but others say not needed if its a Hurst shifter mounted to the trans. Not sure on that one.

4. Driveshaft yoke change. Here too I've seen some mixed answers. Not sure what the right answer is if I'm going from a '73 TH400 to a '76 BW T-10.

5. Will my auto starter fit? Again I've seen answers saying yes and no.

I really appreciate any advice you may offer.

Thanks again,

Jim

 

Let me try Jim:

1). No
2). No
3). You'll need to weld or bolt on a tab for the z-bar for the clutch to the frame. The Hurst shifter bracket attaches to the top of the transmission. Don't remember on the BW.
4). No idea
5). Yes

 

Thanks for the quick response. I really appreciate the answers.

Jim

 

#4 yokes are the same between t-400 and a B/W Super T-10

 

Fantastic, thanks again.

Jim

 

Here is my thread if it helps:

https://www.corvetteforum.com/forums...on-thread.html

 

Jim-81 Thanks for sharing the link, that's very helpful. I just one question about the cross member. I'm looking at picking up a complete set up out of a '76. The owner says there is a bracket that bolts to the cross member and attaches to the 4-speed trans. The shifter is mounted on the trans. Some of the 4 speed cross members I've seen either have the manual trans that appears to sit right on top of the cross member and other appears to have a bracket welded to the cross member that extends forward where the manual trans bolts. The bracket the owner is including does appear to bolt to the cross member and then extend forward. Does this seem like it will work for on '73 that came wit a TH400 trans?

Thanks,

Jim