Suggestions appreciated

Discussion in ''Da Nailhead' started by Dragdoc, Sep 28, 2018.

  1. 66electrafied

    66electrafied Just tossing in my nickel's worth

    OK; Fuel Injection is neat, but a lot of guys I've talked to who've done conversions (on others, not necessarily Buicks) have complained of running problems and that it takes a long time to properly dial it in. Once done, it seems to work. Electronic ignition is nice too, same thing though, some guys have it easy and never have trouble, others can't seem to get it to work, and this even when installed by the same person or shop. So it all comes down to how much you want to spend and how much fiddling you want to do. Up to preference and my personal opinion is to just use the Carter AFB that the cars came with, they're easy to work on and fairly available. My car has no issues with cold start and yesterday it was about freezing and it fired up quickly and held. It's all in the way it's tuned.

    As for power: I used to have a 60 Invicta with a 401 and it was a screamer. It had more than enough power to do what I needed it to do. I have no idea what was in it for an axle, I think it might have been a 3.42, it sure performed like it. That was also with the original Twin Turbine Dynaflow. Your LeSabre is probably equipped with a 3.07, the optional one was a 3.26 which did come stock in Invicta and Electra. There was a 3.91 available, it's stated that it was for export use, I have no idea whether any were fitted. Figuring out what your rear end is will also determine what you need to do to maximize the engine performance to match it.

    Your basic 364 had 10.25 to 1 compression and was rated for 250 hp and 384 ft. lbs torque, as long as it wasn't the regular gas option. That was much less. The base 401 was 325 hp at 445 ft.lbs torque, which is much more effective. It's the higher torque you want, not necessarily the horsepower. A 425 has even more torque, so it would conceivably be better.

    Bottom line: it totally depends on how much you want to spend. To convert the car to a more modern open driveline and modern engine management is going to be expensive and time consuming to set up properly. Of course it can be done, and those who've done it will tell you it was worth it. If you want to stay on the cheap side, get a 59-63 401 and be done with it, it's a direct drop in. Your call...
    gsgtx likes this.
  2. claude brooks

    claude brooks claude

    keep the 364 put a 4 barrel and dual exhaust,i think the 364 is the best nailhead.
    300sbb_overkill likes this.
  3. Stevem

    Stevem Well-Known Member

    If you want it to get going swifter from a dead stop up to let's say 3000 rpm you need more rear gear, more engine cid or both, along with a distributor recurve for icing on the cake.

    The above recommended swap to a 4 bbl set up will not help out any below 3000 rpm , nor will a bigger Cam or a bigger Exh system in terms of get up & go power and throttle response!!!

    While on the subject of Cams and power your timing chain with 47,000 is making for making for retarded timimg to some degree and far lower cylinder pressure then you should have which translates directly into how much low speed power the motor makes.
    A chain and gear replacement would be the very first thing I would do when it comes to unbolting things!
    A seemingly small 1/8" of chain slop translates into a 4 degree restarted Cam setting when the motor is running and that inturn will make for at least a 20 psi drop in cylinder pressure from what you should have and that amount of drop off is not to taken lightly!!

    Have you checked the motors cranking compression on all cylinders, if so how much do you have ?
    Last edited: Dec 19, 2018
  4. Dragdoc

    Dragdoc Well-Known Member

    Ah, thats very interesting. Timing chain stretch.

    I certainly appreciate all the input fellas and will approach things with fresb eyes in springtime. For now the ol’ boy is hybernating from our northern midwest weather. Plus I’m deep in another project at this time.

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  5. 64 wildcat conv

    64 wildcat conv Silver Level contributor

    Be careful with the recurve kits. They are designed with SBC in mind. If you use the timing limiting spacer that comes in some of the kits you'll end up with 38 degrees total mechanical advance. Too much for a nail. It will knock like crazy. I ended up making my own spacer to limit total mechanical advance to 32 degrees, kept the original weights, and used the springs from the kit to obtain full advance at 3000 rpm.
  6. BuickSpecial41

    BuickSpecial41 Active Member

    Hey Mark, what specifications (or guidelines) did you use to make your own spacer? I'm still learning about this so I'm trying to gain all the input I can for my own 401.
  7. gs66

    gs66 Well-Known Member

    Put in the overdrive and hit the Power Tour!
  8. Mark Demko

    Mark Demko Well-Known Member

    Me neither, you pay a couple thousand, plus the labor to convert.
    After all that its still delivering fuel into the same manifold and the fuel still has to travel the convoluted passages as if were delivered by a carb.
    To top it all off, its Throttle Body Injection, the earliest, most barbaric form of mass produced fuel injection.
    If your talking Port Fuel Injection, now theres an advantage:D
    Direct Injection, now were talking high tech for old iron:cool:
    gsgtx likes this.

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