so if i stumbled accrossed a cheap running 66 401 with 400sp from a full size how hard would it be to just drop it into my 66 gs for now while i rebuild the original. the motor in my car is frozen and i have no idea on the trans. i know the trans in the car is a 300, i have to imagine the tailshaft is longer but would i need differnt cross members mounting. i have not bought it yet but im debating.
Basicly, what you will need to build is the factory set up for a 65/66 skylark gs.... you will need the frame mounts, engine plates and motor mounts,,,, exhaust manifolds, head pipes,,, starter, the rear cross member has to move back 5 in.,,,, radiator, air cleaner,,, engine compartment wiring...engine brackets, pulleys, water pump,,, ect.... it is a bolt in swap , but not a simple,quick swap.... there are details that will have to be worked out....
it is definatly possible. im just not sure of the condition of the trans thats in it. i figured i would just pull the motor and trans and swap while i am rebuilding the original 401 and trans.
Yea what doc said he helped me a lot on my swap and I've got everything running now. If you already have a 401 in the car you should be able to just re use the brackets etc. Switching oil pans back and forth might be a pain, I was able to take the 340 out of mine and put a 425 in without too much trouble. I did have to get brackets, oil pan, new radiator, etc and this was my first time to pull a motor and take on something like this but I did it and I think if I can anyone can.
i figured i would be using all of the accesories and things off of the original 401, i figured the rest would be the same. i may just try and use the running 401 and the original trans. just figured the 400sp would be a better trans then the 2 speed thats in it.
so you think the full size oil pan will be different then the gs? i thought only the rivi pans were different. but i also dont know a darn thing about nailheads lol.
im not, i had another posting in the trans section asking which trans should be in the car and only one person spoke up and told me it would be the st300. i couldnt believe a 401 would have the little trans behind it but i havnt been near the car in a couple weeks.
2 things.. the crankshaft ends are diffrent on the 63 and earlier nailheads so they will only mount up to something like a dynaflow. Oil pan issue is this, the rivs and other buicks used a mid sump oil pan and the gs used a rear sump oil pan to get over the crossmember. There are some earlier nailhead oil pans that work to but remember they have to be a rear sump oil pan and you will need a rear sump oil pick up. This can all be avoid if your donor engine came from a skylark gran sport. Where did the engine come from?
66 full size. car was rotted out but ran well. it was cheap enought that i figured i could get the car moving around under its own power while i rebuild the originals. might just say screw it and let the car sit while the rebuild happens.
Hey you could always sell the running nailhead for some cash to rebuild the other. I would make sure you go with someone that has experince rebuilding the nailhead though.
yea from the reading it seems like its a little more touchy then one of my 455s. im still trying to get it freed up. car only has 67k on it and when i pulled the intake and valve covers its clean as can be inside. just sat for 5-6 years. im going to try unhooking the torq converter and turning it by the flywheel instead of the front crank bolt only to make sure its the engine and not the trans thats froze up.
ya know i just looked up trans filters and other trans parts while im here at work and everything i list says 400 trans. that has to be whats in it which means i might just get away with switching pans and oil pump pickups and be ok for a while.
Yep,,, the rear sump oil pan and pick up too..... if it already has a th 400 behind it the engine is most likely later than a 63.... to check whether it is a switch pitch look at the electrical terminal on the left side... it should have 2 terminals....also you will have to change the front yolk on the drive shaft..... and shorten the drive shaft....
yea im really thinking ill pick up the extra motor and trans either way, then determine what i want to do. doesnt hurt to have a spare motor and trans right?lol
doc i also picked up an extra intake manifold that i was going to try your conversion on. anything i really need to watch out for?
'66 was the only year that the Nailhead used a quadrajet carburetor. The intake manifolds are rare and have value.
