I don't know if anyone mentioned it yet, But when you floor your dynaflow it should be equivilent to starting out in "L." Your "kickdown" should basically put it in L when you floor it. The nailhead in my '59 has never been rebuilt and I could spin the tires from a stop when I floored it. Keep in mind that Dynaflows do not have gears. They work off turbines
Got kind of a similar question/problem......Bought a '64 Flxible Premier Combination based on the Electra. It has a cracked block and head. I bought a '62 LeSabre as an engine donor and even had the heads rebuilt before I found out about the Dynaflow/400 differences........ Should I continue to build the '62 engine and search for one of the adapters I've read about, or would it be better just to seek out a '64-'66 401 to rebuild?
I'm guessing there is a difference in the bellhousing bolt patters in a 62 nailhead and a 64 nailhead?? I did not know that. I know there is a company that makes adapters but they're not cheap. Might be easier to find a 64-66 nailhead like you mentioned.
Rev, Use the crank, balancer and flexplate out of your 64 engine in the 62 engine. Save the 64 starter as well (it's the one you will need). Have the crank checked. Have the rotating assembly balanced and use main bearings for a 62 401 engine. The heads are the same for any 364, 401 or 425 Nailhead. The 364, 401and 425 bell housings bolt patterns are all the same. The 401/425 crankshafts have different machining on the flexplate end to accomidate the ST 400 (instead of the Dynaflow) beginning in 64.
I know of a guy on Buick-59.com who has a crap load of nailheads if I remember right. He might have one for your year buick that he will sell you. I cannot find his email, but his name is Marty and he is the president and CEO of NW speed equiptment who specialize in buick parts. If you can find their site send him an email. If not then send me your email and I will pass it a long to him. He might be on this site. He goes by "59collector" on Buick-59.com
Man, that was easier than it original sounded. haha I've been workin on putting a 1970 Muncie behind my 1959 389 Pontiac motor. It's been an adventure finding parts to make everything fit. Glad to hear yours might go smoothly!
The bell housing bolt patterns are all the same. The cranks are the same except for the back flange that the flex plate bolts to. from 63 on back to mate a th 400 to a nailhead you would need to open the center hole in the flexplate to go over the earlier crank. The bolt holes are the same. All you need to do is make the hole bigger keeping it centered ,so a machine shop would have to do it. Balance will not be affected.
