1962 nailhead tranny

wopcycle · 04-30-2006, 03:03 PM

Can some one please help me, I am new to the nailhead society, I have a`1962 Buick Invicta convt. It has a 401 nailhead and a dyna flow. I would like to change the tranny out to a 1964 or 1965 3 speed buick tranny. is this a direct bolt in. If so is it worth the swap. Or should I just bite the bullet and do the adapter chevy change over. any help would be great. Thanks Vinnie.

**chrisj** · 05-01-2006, 04:44 AM

Depends on where your starter is mounted. If the starter is mounted on the engine, you should be able to find a Turbo 400 that bolts in. If the starter is mounted to the transmission bell housing, you need an adapter. There is an adapter for Pontiacs that might work with the Buick, but I'm not sure. Hope this helps,

Chris

**davidb59** · 05-01-2006, 06:45 AM

The nailhead is an externally balanced motor. The flywheel has to be changed which will affect the motor balance. Also, the crankshaft hole in the dynaflow flywheel could be larger to accept a larger crankshaft end on the older nailhead crankshafts. This could lead to major headaches. I discovered this when I installed a 63 T10 4 speed setup behind my 64 425 Riviera.

davidb59

wopcycle · 05-01-2006, 08:55 AM

Thank you for the info, it was a grat deal of help

**butchpruitt** · 05-03-2006, 07:18 PM

Hi, Bendsten Adapters can fix you up with all you need.

**telriv** · 05-04-2006, 03:31 PM

What your asking is, yes, it is a bolt-in swap if you use a 400 trans. from a NailHead. Now come the butts. The NailHead is both internally & externally balanced. A 401/425 has an approx. 4 1/2 ounce imbalance on the flexplate (for DynaFlow) or flexplate for "NailHead" SP or TH400. The 400 flexplate will bolt-up to the DynaFlow crank but the centering hole is too small. Don't, & I repeat, DON'T cut the hole to make it larger. The small lip you see on the inside ID of the 400 flexplate is to add strength. Remove this & you lose some strength. I know others wil chime in & say they have done it, but if you start driving at all spiritedly ( & you will with the new found power) you will be replacing flexplates. They are getting harder & harder to find & it's starting to show up in the prices being reflected for used flexplates. They are not available new. One very big CAUTION!!!! Line up the indexing holes (they should be lined up on your original flexplate, pay attention to this when removing your flexplate) when you install the 400 flexplate or else your engine will vibrate like no tomorrow. The fix for the crank/flexplate problem is an adapter that I can get. The next thing is the starter. Your nose will be too long so you will have to get a '64-'66 starter, or make a spacer to bring out your starter or purchase one of my mini's. Next is crossmembers. It will have to be relocated or get the one off the donor car. Next is the driveshaft. You will need the yoke off the donor & swap to your shaft & maybe even have to get it cut & rebalanced. If your lucky the shaft will be the proper length for your car from the donor. Next is shift quadrent. You have P-N-D-L-R. The '64/400 is NOT a switch-pitch & will have P-R-N-D-L. Or a '65-'66/400 is a switch-pitch & has P-R-N-D-2-1. You will either have to remember this or change your indicator. Playing with shifter linkage is another area. If the donor is a colomn shift use the linkage from that & modify as nec. to work. It may just bolt-in. Now the 400's have an electric kick down switch & also a micro switch if the 400 is a switch pitch. Do a search on wiring for the switch pitch or kick down on many Buick sites. It would take me hours to type & try to explain.
This should keep you busy for a week-end or two, but the resulting improvement in acceleration & fuel economy, in my opinion, is well worth the conversion.

Tom T.

**jpage** · 03-04-2007, 07:12 PM

Originally Posted by wopcycle

Can some one please help me, I am new to the nailhead society, I have a`1962 Buick Invicta convt. It has a 401 nailhead and a dyna flow. I would like to change the tranny out to a 1964 or 1965 3 speed buick tranny. is this a direct bolt in. If so is it worth the swap. Or should I just bite the bullet and do the adapter chevy change over. any help would be great. Thanks Vinnie.

E-Mail me jncpage@comcast.net
I have done it...

**lentzjj** · 05-25-2010, 12:17 PM

ok so im bringing up an old thread. I just got my 400 into my 62 lesabre
the question i have is the starter. The dynaflow starter will go in all the way the only problem is the extended gear on the bendix. So why not just replace the bendix with one that has a shorter gear. I have already done this but ran out of time on the weekend to try it out. The bendix is identical to the original cept for the gear is short enough that it can disengauge. Anyone have a reason why this wont work?