change from manual to automatic

[rizick]

I am wanting to put an automatic in my 66 stepside. it had a 6 cylinder with a 3 speed manual. I found a 327 from another 66 and currently we are rebuilding it. Any ideas or suggestions would be helpful, I have changed a few engines and trannys but cant say I have ever converted from manual to auto and would like to keep my mistakes to a mininum. Kind of thought about a 3 speed auto or something with an overdrive. I am worried about linkage and the drive shaft issues, I am sure I can find a automatic tranny mount, and was thinking about a tiltsteering column from performance parts or someone like that.
thank you

[greg64]

Howdy rizick. I've actually gone both ways on the tranny conversion over the years. Going to auto was by far easier. Okay, here's what I know:
1) Go for the overdrive now (700R4). You'll thank yourself later.
2) Ring gears come in two different sizes and bolt patterns for the torque converter. The larger has 168 teeth and the smaller 153. I'm not sure which bolt pattern the torque converter for the 700R4 uses, but many of these ring gears are drilled for both patterns.
3) Make SURE that the bolts that hold the ring gear to the torque converter aren't bottoming out against the converter. I had this happen, and it led to a damn annoying vibration that took a year (!!!) to figure out.
4) A floor shift (B&M, Lokar, etc.) will be easier to couple up than any column shifter. But of course, both are possible.
5) The 700R4 uses a TV cable that HAS to be adjusted properly. It's not just a kickdown cable like the TH350 uses and if not adjusted properly can fry the trans.
6) Install a supplemental tranny cooler, as well as the in-rad cooler. When towing or climbing big hills, the rad cooler alone doesn't cut it. And, make sure the order is out of the tranny, to the rad cooler, to the aux cooler, back to the tranny.
7) Different starters are used depending on how many teeth are on the ring gear. 153 tooth RGs use a starter where the two bolts are directly across from each other (perpendicular to the crank). 168 tooth RGs use two bolts that are staggered.
8) You will likely need a new driveshaft made, but this is a good opportunity to get a freshly balanced shaft with new U-joints. Take your old shaft to the shop because they may be able to use part of it, and it will FOR SURE tell them what U-joint you have on your differential (I've had past problems with this).

I'll probably think of some more things that I'll add to this post.

[62 short step]

Greg64 gave you some good advice, the only thing I will say is go 700r4 you will love it. Thats what I put in my 61 4x4 and its great.

[rizick]

thanks greg64
where would I shop for a 700r4 transmission and I really would like to have the shifter on the column. The tv cable you spoke of is not something I have ever heard of. thanks again

[greg64]

Rizick, if I were looking for a 700R4, I'd take one of two paths:
1) buy one off Craigslist (they're listed here quite frequently) and take it to a shop for a go over.
2) talk to a local transmission shop, as many of these guys who rebuild trannys will rebuild cores they've come by in their "down time" and then resell them.

The TV cable isn't that scary, it modulates the line pressure in the transmission. It needs to be connected in parallel with your throttle cable and adjusted appropriately. Tim64 was just going through this on his rig. The worry is that the pressure is too low when you've got your foot into it, which would cause the bands and clutches to slip, ultimately burning them up.

[1966gmc]

I did it not too long ago.I bought a th350,converter,flexplate,speedo cable,starter,th350 slip yoke,new u joints,auto trans crossmember,dipstick and a floor mounted shifter.I bought a 12 in flexplate and converter so I had to buy a 153 tooth compatible starter(86 corvette).The stock speedo cable was too short.Replacement bought at autozone for a 78 c10.You can just unbolt the clutch assembly.I had a kickdown cable lying around.I had to cut out the stock crossmember and drill holes in the frame for the "bolt in" auto crossmember.Change out the slip yoke from a 10 spline to a 27 spline yoke.I was able to keep the driveshaft the stock length.Im trying to think if there was anything else.If you have any questions just pm me and I will be able to help you out if needed

[TINKERDUKE]

If your hunting down a 700r4, i believe the later ones are stronger.

[Fred T]

For more info go to www.bowtieoverdrives.com

[rizick]

Thanks all for the help. I did check out that bowties web site. It was very informative. Some of the websites offered new ones or rebuilt ones at what seems like reasonable prices. I am still a little unsure if I am going to be able to use a column shifter without much trouble or jury rigging. Thanks again