[bigunde]

Looking at replacing the Turbo 400 in my 66 with a 200r4 and wondering if its a pain to do. Im currently running a 60 over 1970 455ho engine with the 64 heads and powermax cam.Thanks

[camerjeff]

I did it with a 66 with a ST-300 2 speed trans, Not that difficult at all. I had to slide the trans X-member back, hook up the TV-cable, and even the drive shaft & yoke worked with the 2004R. Now it will be slightly more difficult with your T-400, the drive shaft won't work (to short) , and you will have to use the smaller yoke on the new shaft.
Other than that it is just deciding on what systems to use on your carb to hook up the TV cable, I sugest going junk yarding and finding a 82-90 Q-jet from a car with a O/D trans and getting the factory throttle cable bracket from it, you may have to buy the butterfly plate or worst case the entire carb. The bracket is swedged on but the swedge can be filed or milled off easily then I drill and tap the original carbs throttle shaft for a small allen head screw and attach it. The GM engineers did all the calculations for you, and it is a cleaner instillation than the after market adaptors in my opinion. Then you have to decide if you want a lock up converter, and what way you want to operate it. Good luck, I think you will be happy with it if you drive the car on the highway at all, and it will lanch better with the lower 1st gear!!!!

[66Mutt]

I had a Turbo 400 in my car behind my 400 engine and went to the 2004R. There really were not any hangups. I have a His/Hers shift console and Shiftworks has a conversion kit that changes the detents to 4 speed from 3 speed. I had the yoke replaced and I don't remember if the shaft length was any different. About the only unexpected thing that I encountered was the effect it had on the emergency brake cable. The crossmember is moved back and therefore the e-brake cable length is altered due to the change in geometry. I have the lockup converter but often on residential streets I run it in 3rd gear because convertor will lock up in 4th at very low engine rpm's. I am thinking of wiring in an rpm window switch that would not allow it to lock up until it is 1800 rpm or higher.
Doug

[vamman1]

Same here. @ 70mph, she only changes to 4th gear! Quick in first as well.

Throttle bracket and TV cable bracket will definitely have to be modified.

I can get a picture in a day or so.

[FSJplumcrazy]

Did you use the factory cross-member or did you find/fabricate a new one?
I have to do this on the convertible so I don't have the luxury of the C-channel

Suggestions?

Wayne s

[66Mutt]

I have not been under another '66 to know what exactly stock should be. I am not sure my crossmember is stock. When I bought my convertible, it had already been converted to a Turbo 400. It does look like they may have welded some additional Cross member flanges on the frame rails to move the crossmember further towards the rear. It looks to me like there are two of the flanges with multiple holes in each. Then again, not having been under another '66, I assumed this was not stock, but given different powertrain options maybe they had what I am guessing is 8 to 10" of different hole options.
Doug

[vamman1]

Used the same crossmember on my '67 convert.
Used the mounting bracket from the old ST-300.

Good time to install new rubber bushings on the crossmember and check ends for corrosion.

[lust4speed]

If the driveshaft is the right length for your T400, then it will be the correct length for the 200-4R (well, the T400 is 28-3/8" long and the 200-4R is 27-11/16" long or a difference of 7/16" -- normally close enough not to cause problems). Just needs the proper yoke (back to the yoke that works for the 200, Muncie, T350, etc...). The frame holes were in the proper place on my 67, but we had to drill the 66 frame for locating the cross member.

[vamman1]

It's all coming back to me now!

We moved the transmission mount brackets back 6 11/16" on the frame to accommodate the 2004R different cross member bracket location.