401 into a 66 skylark

Discussion in ''Da Nailhead' started by Captjimmy, Dec 26, 2016.

  1. Captjimmy

    Captjimmy Active Member

    Update / more questions on my 66 skylark engine swap

    I finally dropped the completely disassembled 340 off at the machine shop. I was told that it would run about 500 bucks for the valve job on the heads. Then I get home and as fate would have it, I picked up a COMPLETE rebuilt running 401 sans the tranny out of a 63 Riviera that night for the same 500 bucks!. ( I went to the guys house and heard it run before he pulled it.)
    As such, I have even MORE questions. ( thank you for your patience ;-) )


    I also have a 401 and st 400 tranny out of a 65 riviera that Im still going to rebuild. I was going to take the tranny from the 65, use the 65 flywheel and starter and change out the pilot bearing on the 63. I also have a kick down linkage for the tranny from another car. Will these need to be the only mods I need to do to make the 63 401 / st400 combo work?

    Since the car previously had a 300, I'll need to use mounting plates for the 401 swap. Is there a template somewhere I can use to fab these, or is it easier to just buy them as an after market item?

    The radiator for the 300 wont be up to the task of cooling the 401. I can pick up the radiator out of the Riviera for 100 bucks, but I'm not sure if it will fit in the Skylark. Should I get it and just modify it? I see Skylarkl GS radiators on eBay for 149.00, but they're a 3 core and Im not sure if I need a 4 core crossflow / downflow one, etc.....

    The driveshaft will probably need to be shortened. Can I just cut down the one from the 300 and will it be able to handle the added torque? Or do I just get one from a Riviera ?

    I've already cut and moved the battery tray

    Will the tranny mount for the 2 speed auto that's in there work for st400? I'm pretty sure Ill have to move it back, just not sure if it could be modified to work.



    I was also told to get stiffer springs for the Skylark due to the bigger motor. Would the springs from the Riviera work? Would I need to cut them down? Is there a particular after market set specifically designed for this application.


    And finally, What else am I missing?
     
  2. John Codman

    John Codman Platinum Level Contributor

    Hopefully Tom Telesco or Doc will jump in here. I don't think that taking a Dynaflow 401 and bolting it to a THM is as simple as just changing a pilot bearing. I know that it can be done, but I would want to be absolutely sure of the procedure before I attempted it.
     
  3. Captjimmy

    Captjimmy Active Member

    Its def turning into more of a project than I thought. Even without swapping the trannys there a gob of stuff to do. I'd rather ask questions and get it right ( hopefully ), than put it all together and have to pull it all back out. Hopefully I can use the already running 63, and take my sweet time putting together the what Ive now been told is a 66 401 and make it a thing of beauty. I hate asking all these questions, but sometimes its easier to ask questions than keep making mistakes.
     
  4. SpecialWagon65

    SpecialWagon65 Ted Nagel

    There is a template for the motor mounts somewhere on this site...
    yes transmission crossmember will have to move back and your driveshaft can be modified-mine held up for a little while
    with a 455. you will probably need exhaust manifolds from a 65/66 GS as well.

    None of the Riv stuff you mentioned will work - driveshaft or springs...you need to study the
    flexplate fitment and torque convertor fit between 63 and 65 motors more carefully.
    You may wish the 340 back; $500 bucks will not get you near the finish line on a 401 install IMHO.

    Lots of fun when its done!
    Ted
     
  5. wkillgs

    wkillgs Gold Level Contributor

    The 401 into a 65-66 is a rather involved swap. You'll need many GS specific items such as:
    - Frame mount pads, engine mounts and adapter plates. You'll need the original GS frame pads, the adapter plates can be fabricated, and the repo rubber mounts are available from the Buick Farm. You can also use the 3-bolt chevy rubber mounts instead of the GS 4 bolt pads if you are making the adapter plates or are willing to drill new mounting holes in some original plates.
    - Rear sump oil pan and oil pump pickup from 65-66 GS. There was also a rear sump pan used in the late 50's, unsure if it has enough crossmember clearance.
    - 65-66 GS exhaust manifolds or headers from TA
    - Engine wiring harness from 65-66 GS. Avail as a repo.
    - Radiator has different in-out locations than most. Get either a 65-66 GS-repo or a aluminum universal for a 60's-early 70's Mustang or mid size Ford. Might need the repo rad mounts and top plate if you use a wide-tank radiator.
    - Front springs, Moog #6033 are direct replacements for the 66 GS springs. 6197's work well for the rear.
    - The <63 crank shaft has a different flange than the 64-up. You'll have to grind off the lip from the 63 crank and buy a crank adapter adapter for the 64-up trans. use the later flexplate.
    - Trans crossmember has to be moved back for the longer st400 trans. EDIT.... The Skylark crossmember will work, just drill new holes in the frame to mount it. (GS or convertible frame needs a mount welded on)
    Do you have a console shifter? It'll need the cable adapter kit from Shiftworks.

    Obviously, all these items add up! Buying them separately at market price gets crazy. Try to find a GS parts car or someone parting one to get a package deal on the parts.
     
    Last edited: Dec 29, 2016
  6. John Codman

    John Codman Platinum Level Contributor

    Not to discourage you, but this swap, although possible and from the technical standpoint not difficult, will be time-consuming and expensive. Some of the GS-specific items are either hard-to-find and/or expensive. The time-consuming part will be locating them. As was mentioned earlier, finding a donor parts car would make the job much easier. Once you have all of the necessary parts, it's pretty much (with the exception of attaching a THM-400 to a pre-'64 engine) a bolt-in.
     
  7. nekkidhillbilly

    nekkidhillbilly jeffreyrigged youtube channel owner

    my car has a 62 engine.
    I went with gs headers saved money searching.
    im using a adapater and 200-4r so I m no help there. I know russ martin sells the adapter.
    aluminum rad is the way to go.
    wiring harness is pretty simple you could build one or mod your 340 one.
    rear sump oil pan and pickup. the 50s one is the same. there is a repop one but its expensive pretty though.
    pickup you can cut and reweld mid sump to make it a rear if you cant find one.
    crossmember again mine will need to be custom as I am using a real gs frame and the 200-4r. you can build them out tubing pretty easy though.
    all my junk still is in storage cause I cant afford to finish things for now. I think I found frame pads but you could build some im sure pretty simple.
    also open channel frame I think you can just slide the crossmember back and drill holes.
    carb linkage and trans kickdown is different for the 200-4r plus im going to a fitech unit so no help there.
     
  8. Captjimmy

    Captjimmy Active Member

    yeah...... I was afraid it wouldn't be that easy..... looks like I'll find a 350 to keep it on the road for now, and take a couple months accumulating and prepping everything that Ill need. that way I can rebuild and go with the 65 motor and tranny combo and save myself some time and hassle there at least. Im not trying to race it, just looking for a fun car to drive.

    Many thanks for all the input. I knew this was the place to go ;-)
     
  9. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Ya know, a 455 swap would be a whole lot easier than a Nailhead swap, a 455 will even bolt to the trans you have in the car already if it is still good.

    All you would need is '67 frame pads that I think TA Performance sells and '67 motor mounts, a set of 455 exhaust manifolds, a better radiator you may even be able to not have to change the front springs if you get an aluminum intake to lighten the engine about 45 lbs. and of coarse a rear sump oil pan if that isn't on your donor engine, TA sells those too.

    Of coarse you would need the accessory brackets for the 455, not sure if the 340 ones will work but they might? The wire harness from the 340 would almost be a plug and play with possibly a couple minor differences. Battery can stay on the side it came from the factory for the 340 as well.

    The sbb 350 option would be an even more direct bolt in than the 455, with even being able to use the 340 accessory brackets and accessories, frame pads and motor mounts. If you're looking to build a 350 there are a few more options that you can do to make that engine a great runner than there is for the 340!

    Stop buying engines until you get a plan on exactly what you want to do, or you'll end up with more engines than cars to store, plus that takes $$ away from what you'll be able to do with what you decide to go with. GL







    Derek
     
  10. nekkidhillbilly

    nekkidhillbilly jeffreyrigged youtube channel owner

    340 to 350 is a direct swap my car had one in it when I got it. used the 73 accessories all worked. I wanted the nailhead cause I really wanted a gs even though its only half. I didn't care if it was clone or not but I wanted nailhead 66 gs. its not a terrible swap like its been made out to be just requires shopping around. I think a lot of guys get hung up having it look bone stock. the hard part to me is the rear sump pan. the rest really you can find pretty well or make in a few mins. I mean like a kick down cable or rod should be pretty easy to fab something up. wiring harness on this car you could pretty easy extend this wire move it etc.. the big thing is the headers and the rear sump. those are the costly items. Im using a mini starter to add.
     
  11. Captjimmy

    Captjimmy Active Member

    I was thinking about just cutting and fabbing the old pan from the 401 and turning it into a rear one. I didnt know if a rear sump oil pump from a 455 would fit, or is i just used the flange and head from the old one and added a longer tube. I just need to make sure I dont get a lil to freestyle with my fabs :)
    And you're right! Ive now got 2 401s in the garage( the 63 def looks like a newer rebuild job ) and a disassembled 340 in the machine shop. And still no motor to put in the car,.,,,,,,, Def put the money in the wrong places on this one. Got a feeling this might be one of those pricey lessons to learn.
     
  12. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA


    A big block Buick 455 is a different engine platform than the Nailhead. The 455 has an external oil pump that is part of the timing chain cover just like the small block Buicks. The Nailhead has an internal oil pump, I don't think a 455 oil pump pickup will work in the 401.

    Seeing how you have 2 401s perhaps you can look at swapping the later model crank in the '63 block, the balance should be very close, but weighing a piston from each engine would let you know how close. I'm not totally sure the later model crank will fit in the '63 block, maybe one of the Nailhead gurus will chime in to confirm or deny?

    If the crank can be swapped but the piston and rod combos aren't that close in weight you could have the newer crank balanced to the '63 internals? Now you have a trans to bolt to the '63 engine from the newer one as well.

    It would give you the opportunity to make sure that engine will be in good running order before it goes in, just get a basic rebuild gasket and ring kit, ball hone the block for new rings, clean block, install new bearings, check your clearances and make sure everything is torqued together and sealed up the way it is supposed to and good to go. GL





    Derek
     
  13. nekkidhillbilly

    nekkidhillbilly jeffreyrigged youtube channel owner

  14. nekkidhillbilly

    nekkidhillbilly jeffreyrigged youtube channel owner

    also the oil pans is 395 for the new ones that are finned aluminum or used ones go about 300. that and the long tubes are going to be your big money stuff. rest is cheap stuff. driveshaft get a 68-70 th400 with a 8.2 rear from any a body. it should be the same length as you need but solid.
     
  15. doc

    doc Well-Known Member

    well,,, I did this swap into a 64 skylark coupe,,, loooooong time ago....:rolleyes: I used a 1959 engine,, a 66 th400 trans, had to fab a rear crossmember from rectangular tubing,,, had to change the starter up because that swaps sides of the engine , has a different drive on it, ect... must have a 4 tube radiator.. cross flow,,, found one of those out of a early vett.. all the mounts/plates/ect... came from a wrecked 65 GS... had to modify the driveshaft for length, and front yolk type... and of course the exhaust manifolds had to come from a 65/66 GS and the exhaust pipes/mufflers ect.... the stock rear end with the 292 gear was swapped for a 65 pontiac GTO assembly with a 4.11 posi...
    I ran a stock Buick supercat cam with a 950 cfm holley three barrel carb, cold air pkg... that came off of the windshield wiper chamber... via the stock 59 air cleaner /clothes dryer hose,,, :Brow::laugh: on the street it was a sleeper....
     
  16. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

  17. nekkidhillbilly

    nekkidhillbilly jeffreyrigged youtube channel owner

    doc with a open channel frame cant you just do like 4l80 swaps and so forth and just slide the st300 crossmember back and drill new holes in the frame? the 63 is on the same side and the 66 but he still prob needs the 66 starter. I know if he uses a aluminum rad he wont need a 4 core cause of the increase of cooling they have. I think most use 3 core aluminum but I have heard of 2 cores ones getting it done. now the copper brass no way it would.
     
  18. nekkidhillbilly

    nekkidhillbilly jeffreyrigged youtube channel owner


    there odd to say the least. but you use what you can find ya know. the 61-63 are the oddballs for some reason and everything cost a little more for them.
     
  19. Captjimmy

    Captjimmy Active Member

    So with the pilot adapter, flywheel and starter it would work?
     
  20. Captjimmy

    Captjimmy Active Member

    And which one would be more preferable to keep based on year? the 66 in the 66 makes sense, but did one year have something more going for it than the other year? I'll end up eventually rebuilding whichever one I keep anyway.
     

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