LS engine swap cost/adaptability for 70-72 Skylark

Discussion in 'High Tech for Old Iron' started by Christopher Spouse Drew, May 11, 2019.

  1. Christopher Spouse Drew

    Christopher Spouse Drew Well-Known Member

    So, I have a 455 that I need to build, starting to do the head work now. Im thinking about total cost and what I want from the car. Reliability, I want to daily drive the car. I want my family to enjoy the car with me and they always say they can't stand the exhaust smell in the interior. They dont get it.. haha. So with the engine cost for the stage 1 conversion on the heads, block work, all the parts, fuel injection. I'm looking at a total of about 3-4K. I'm a mechanic, I can go to u pay u pull and grab an LS out of something.

    So, I want to hear from the guys that have done the LS swap, what LS do you have? Total cost? Difficulty adapting into our cars? Performance? What transmission? Driveshaft? Rear end? Tell me as much as you can so I can make a decision. Thank you guys in advanced. The only thing I do know is, I'm not getting rid of my 455, it will go in one of my future cars!
  2. GotTattooz

    GotTattooz Well-Known Member

    I bought a 99 Chevy Silverado with a broken frame for $1300.00. I used the engine (5.3l), transmission (4l65e), steering column, dash cluster and complete wiring harness in my 65 skylark wagon (my build thread is in the Wagon section). I swapped intake and oil pan for clearance (2000 Camaro intake, Holley oil pan), bought an alternator relocation bracket from, Holley motor mount and trans crossmember kit, Holley in-tank fuel pump and some LS swap headers.

    I'm sure I have prices in my build thread. The 5.3l is stock except for the intake and oil pan. I'm running 3.42 gears and I get 18-24 mpg, 285 hp and zero reliability issues. Having the complete wiring harness, I also retained the obd2 port, so I can use a scanner to check for any issues, should they arise.

    Last edited: May 11, 2019
  3. docgsx

    docgsx It's not a GTX

  4. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    I can say if you're a decent mechanic there is no reason why the 455 can't be reliable with a carb. It's laughable that folks think anything with a carb will explode at any second... just how did people get along for 90 some odd years with carburetors?

    If you have exhaust leaking into the car you have other issues.. rust holes? Leaking exhaust? Or is it so rich it burns your eyes?
    docgsx likes this.
  5. docgsx

    docgsx It's not a GTX

    An LS is kind of cool for now, put the big block in there when you’re ready and get a good OD transmission so you can make it a DD
  6. Christopher Spouse Drew

    Christopher Spouse Drew Well-Known Member

    I have a very tired 350 in the car now that I wont spend a penny on, its all about the engine I choose to build. I can make the 455 run great, but in the long run, an LS is much easier to diagnose and get replacement parts locally, the gas mileage is better, and it will last longer between rebuilds. and the most important thing to me, the COST! I didnt say anything about carbs blowing up..
  7. dr

    dr Well-Known Member

    Its your car do what makes you happy.
  8. cobravii

    cobravii Well-Known Member

    It is your car and you can do whatever you want BUT my thoughts are the same as 436'd skylark. These cars did not have exhaust smells when new. If you want to use an LS engine then get a chevelle.
    sriley531 likes this.
  9. Ryans-GSX

    Ryans-GSX Have fun, life is short.

    Friend of mine put a LS 6.0L in his Buick and loves it for the fact he can drive it on road trips and it does remarkably well on gas milage. He loves it. He paid a shop to do the work. I don't think it was overly hard for them because the kits make it much easier than in the past.
  10. Mach5racing

    Mach5racing Well-Known Member

    I would love to swap a ls in my skylark someday. The power and reliability is worth it in my eyes. I think with some careful looking around you could do it pretty cheap. I have a friend with a 55 Chevy with a ls and a 6 speed. It is an awesome car. With just a cam swap and a few other things you could be around 400hp which is perfect for a street car. 400 hp out of a Buick 350 would cost significantly more. With that being said my other friend has a 70 skylark with a 455 and a 4 speed. And that car is awesome as well. It’s a real tough decision. But either way you went if your not happy it can always be changed in the future.
  11. GraySky

    GraySky Member

    It's a tough decision. Every time I think about the pros and cons of using an LS engine, I think it's the best logical decision... but it's just not original, and I can't bring myself to do it. Everything has an LS these days.
    If you compare the cost between a 500hp LS and a 500hp BB Buick, there's no contest (at least when you're thinking without any brand loyalty and just looking at specs):
    LS- good oiling system, roller cam, EFI (this IS a big plus), STRONG block, short block that holds up to 800+hp stock, good flowing stock heads, easy bolt on and control for an automatic overdrive, tons of aftermarket support...
    $1500 for a low mileage 5.3 or 6.0, a $1000 cam and valve spring upgrade, and there's your 500hp.
    BB Buick- 5 grand in the short block, 3 in good heads, another 1k if you want a roller cam and not worry about oil issues... still stuck with a carb unless you drop another 3k on EFI... and then you end up with a motor that still has a weak block. Never mind the appropriate carb and distributor upgrades / rebuild, headers, aftermarket intake, new front cover, etc.
    Still, there's nothing quite like the Buick torque.
    blyons79, ceas350 and Mach5racing like this.

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