I'm in the process of buying a 425 nailhead/ST-400 combo, out of a long gone 64 Wildcat (originally a dual carb. set up), dropping it in my 66 Skylark (the motor/tranny have been in an old trailer for well over 25 years, because of snow I won't be able to physically get to it to move it out, until spring). BUT, I've read somewhere (musclecar performance mag., I think?), that the 64 ST-400 should be avoided. Can anyone confirm or deny that, maybe provide me with some background info.? Also, will this fit where the ST-300 is now, without too many headaches, drive shaft probs. etc.? This tranny was supposed to have been rebuilt, only 20K put on it before it was pulled, what servicing should I consider having done to it, before I can be satisfied that it won't fail, ten miles down the road? It's not carved in stone, but I noticed what turned out to be tranny fluid, seeping out from under the garage door the other day - lot's of it, leaking from my Skylark, not pretty. Rather than spend another cent on a tranny that I'm gonna have to replace anyway because of all that nailhead torque, I'm considering doing the tranny switch first. That said, what other trannys should I consider, cost, availability etc? And lastly, I'm thinking of calling Carmen Faso to discuss the motor rebuild, does anyone know if he does tranny work too? Thanks guys, Denis
Dennis, The Nailhead has its own unique bell housing bolt pattern. The ST 400 behind the 425 will not bolt up to the 300 or 340 in the 66 Skylark as these engine have the more common BOP bolt pattern. When you install the 425 and ST 400 you will have to move the transmission cross-member back to the next set of holes in the frame in your Skylark, install a larger ST 400 yoke, and have the driveshaft shortened by about 5/8" or so. The 64 ST 400 does not have a variable pitch converter like the 65-67 ST400, it has a stand alone valve body, and it has three forward gears with only two of them available (drive and low) for selection. It is still a good, tough transmission that will last indefinitely if properly built and serviced. Most reputable transmission shops should be able to service this transmission as it does have a lot in common with the TH 400. Carmen is definitely the man to contact regarding a Nailhead motor build. It is a lost art to most others. Cheryl
Agreed. I've never seen any downside to a 64 ST-400 except the lack of variable pitch. I've got one with at least 149,000 miles on it, all original.
