OD trans ?'s

[bbbbuick]

Howdy all,

Looking at finally ditching my SP300 for an OD trans. I've got a posi 3.55 rear and with the 300 I'm just pulling waaaay to many RPMs on the highway. Finding a new posi gear set for the diff has proven to be quite challenging and after talking with Jim at JDRace I think more gears may be the better way to go. I've read through the various posts regarding this, seems the 200R4 is the best bet for least amount of modification. Can anyone flag any other known issues with this mod please? Saw that Walt posted that the crossmember needs to move. What about driveshaft length/nailhead bolt pattern/etc.? Currently a numbers matching car so save the old trans in case I ever sell (don't intend to but you never know). Thanks for any info you can share.

Elvin

[Rollaround]

The 4L60 has a modular bell housing, there is a direct fit 4L60 to nailhead bell housing available. CARs has it, a bit pricy but eliminates the need for an adapter from the nailhead to the 200R4 and the need to cut your tunnel. The 4L60 also has a deeper first gear. I have one in a 65, things line but well but you do need to move the crossmember aft but it's no big deal. Shiftworks has a shift kit that goes well with the GS console. Talk to your tracy guy about beefing up either trany to handle the nailhead toque.
You'll enjoy seeing the rpm drop from 3000+ to 1800 or 1900,  you'll ask yourself why you didn't do it sooner.

[elagache]

Dear Elvin, Kevin, and mid-60s Buick cruiser fans . . . .

I've read through the various posts regarding this, seems the 200R4 is the best bet for least amount of modification.

My trusty wagon has had two 200-4R trannies.  The second one is from Art Carr California Performance Transmission.  Both times there was no problem with changing the length of driveshafts or changing rear end ratio (I have the 2.78:1 rear end still!! )  I went with a new crossmember from these guys, but my understanding is that you use old crossmembers:

http://www.crossmembers.com/

You'll enjoy seeing the rpm drop from 3000+ to 1800 or 1900,  you'll ask yourself why you didn't do it sooner.

DITTO!!!! 

Cheers, Edouard 

[bbbbuick]

Thanks, that pretty much reaffirms what I was thinking. Did not know the tunnel had to be modified to fit the 200. Would the internals still have to be beefed up for regular street cruising with occasional strong application of right foot? Not tracking this car at all. Does it make more sense to get an aftermarket driveshaft rather than cutting down the original, maybe better balance or lighter weight?

Elvin

[Rollaround]

Here's an interesting chart on various transmission gear ratios      http://www.oldengine.org/unfaq/leadfoot/trans.htm  A .67 OD will drop your rpm by about 1/3.or 33%.
If you change rear end gears it will add to the RPM reduction.
Her's another interesting chart to look at.  ://www.ringpinion.com/calculators/Calc_RPM.aspx

elagache, are you running a later generation non-nailhead engine?

[Buicknut65]

I'VE HAD 200R AND 700R ON 11 TO 1 300 AND 200 R WAS BEST BY FAR STOCK . I HAVE A PRO BUILD 700R WITH ADAPTOR BEHIND MY 401 2X4 AND IT'S AWESOME WITH 410 GEARS .

[bbbbuick]

Thanks for those links Kevin. 2000 RPM on highway would be much nicer, which looks like what I get with the 200R4 or better with the 4L60. Does the 4L need a computer to run correctly? I am seeking simplicity, no internal switches to flip for OD functionality, and I would really like to not have to mod the tunnel to fit the trans. Read that getting a 200R4 from a carb car eliminates computer snags. Crossmember is pretty straightforward and could be changed back if desired so I was hoping for only that adaptation.

[elagache]

Dear Elvin, Kevin, and Mike,

elagache, are you running a later generation non-nailhead engine?

Oops sorry guys, forgot to ask what engine this tranny was going behind.  The 200-4R is happy with the later engines starting with the 300 cid.  I never looked into the tranny options for the nailhead.  As you guys say, the 200-4R does not seem to be the best match for the nailhead.

I stand corrected!

Cheers, Edouard 

[Rollaround]

There are several different stand alone 4L control units out there and they're pricey units. Somebody might chime in that has installed a 200r4 behind a Nailhead in the 65 body.
It is my understanding (I've been wrong before) that the 200 adaptor sets the trany back so far that the tunnel needs modification.

[bbbbuick]

So it sounds like the 4L60 is the way to go. Isn't the 700R4 the same trans? If so then I've got a line on a good one that I can get rebuilt with beefed up internals. The guy who has it says it's a 1987 model with larger spline shaft and the TV cable which apparently is good to get with it. Not cheap though, I'll just have to try to focus on how much more fun it will be to drive. I'll look around at other posts re: 700 compatibility behind nailhead. Does anyone have a good source for the adapter plate to mate it to the block?

[WkillGS]

Bendtsen's has the  adapter to mount a Chevy pattern trans to the Nailhead:
http://transmissionadapters.com/53-66_nailhead.htm

Another option is to add an overdrive unit to your existing trans. It's made by Gear Vendors. About $2700:
https://www.gearvendors.com/hrgm3s.html

Russ Martin/Centerville Auto Repair has the 4L60E adapter:
http://nailheadbuick.com/transadaptors