I have a 67 with a 350ci and a 350 turbo trans. I have decided to do a 700r4 swap and was wondering if there is a specific year of the 700r4 that I should be looking for or staying away from. Thanks

 

'86 or newer. I believe that was when they updated them. You can go up to '93 in cars, '92 in trucks. After that they were electronic.

 

1987 is when they made internal improvements, stick with that year and newer if you're planning on doing a drop in swap with a known good trans. Otherwise, the previous years can be upgraded when being rebuilt, but the 82 & 83 had weaker 27 spline input shafts (84-up have 30 spline). To keep the lockup function, you can get a kit from Summit or Jegs, or hotwire it with a toggle switch. You'll also need to have your driveshaft shortened, and modify or replace your trans crossmember.

 

Thanks for the good information. I will look for one in those years.

 

You might want to do some research. The 700R is a good economy trans, but the 1-2 gear ratio spread is huge. I think it's like 50%, which can take your engine out of the power band. The more I research, the more I'm convinced that I'm either going with a TH tranny or a 4L80 trans.

The 4l80 trans has the same ratio as the TH400, just with the overdrive. From what I understand, it basically IS a TH 400 just with an OD gear.

 

Here's the article I was looking for:

https://www.gearvendors.com/hrgm4s.html

Here is a better one:
http://www.jakesperformance.com/4l80/

 

FYI, the 700R4 is a TH trans. Full name is TH700R4. 1st gear is a deep 3.07 and 2nd is high at 1.63, but I've never had an issue with the shift dropping me out of the power band.

4L80E is nice, but you have to have a computer to operate it. The 700R4/4L60 is all hydraulic.

 

Thanks for the feedback. I would like to race on occasion, that 1-2 ratio split is just not very compatible with drag racing. That steep of a 1st gear could make you redline at something like 30 mph. Contrast that with my Z06 which will do over 60 mph in 1st gear.

As to the computer needed for the 4L80E, that's basically true as I understand it, UNLESS you get the full manual valve body.

As that article explains, the huge 1-2 gear split in the 700R4 builds up heat. And lets face it - there IS a reason that performance transmissions typically have a "close ratio".

Don't get me wrong, if I found a great deal on the 700R4 I'd take it, but I would most likely go with an actual TH400 or 4L80E before I went with the 700R4 - personally.

 

One overdrive transmission being forgotten about is the 2004R. It's a direct swap for the TH350, uses the same driveshaft, the crossmember has to move back a little bit. It's an easier install than the 700R4, and 1-2 gearing is better than the 700.
2004R- 1st: 2.74, 2nd: 1.57
700R4- 1st: 3.06, 2nd: 1.62
TH350- 1st: 2.52, 2nd: 1.52
TH400- 1st: 2.48, 2nd: 1.48
Bowtie Overdrives

 

I considered that, it's just a pretty light duty trans. At some point I'd like to be near 550 - 600 HP. I just don't know if I can trust this tranny to be reliable at that power level.