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- High 10's Secrets for Your Buick 455
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- Buick 455 Drag Strip Tests from Kenne-Bell
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Thread: 1970 455 Rebuild Question

  1. #1
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    1970 455 Rebuild Question

    Hey Guys,
    im going to start working on my 1970 455 but don't want to drop a ton of cash into it. It's an SF code motor that from what I can tell is supposed to be 370hp & I don't really want much more hp than that. If I can get it to around 400hp without spending a lot of money I wild be more than happy because I want to be able to use pump gas & get decent gas mileage. I just finished reading the 455 rehash article from car craft which is basically not much more than removing the accessories & repainting it, which is about right in my wheelhouse for price. The only other things I want to do are a new cam, lifters, harmonic balancer, & timing chain. If I put a new cam & lifters will my stock heads still work? Is there any work that will need to be done to them? What are some suggestions you guys have for new cams & lifters that will get me a little to the 400hp range without breaking the bank or can I just reuse the original stuff to get me there? I would also like to know what you guys think about using a 700R4 tranny behind this thing & how I can make the 2 work together.
    Thanks in advance.

  2. #2
    make sure you've got the Stage 1 valves.

    upgrade the distributor to a 73 and newer HEI unit.

    even if you don't do any other oiling upgrades, get the 73 and newer 5/8" dia oil pickup. it's a bolt in swap, too easy not to do.

    get one of the 71 and newer 800cfm Quadrajets ( yours is 750 ) and have it rebuilt by a reputable Quad builder.

    install full dual exhausts.

    stock rockers should be good up to .490 lift. make sure your springs are in good shape ( they are 40 years old, after all ) but stock replacement should be all right as you shouldn't be spinning over 6000.

    a 200r4 would be a much easier swap. the 700r4 has a Chevy bell and will require an adapter plate.
    The way to crush the bourgeoisie is to grind them between the millstones of taxation and inflation.
    Vladimir Lenin

    Government schooling is about "the perfect organization of the hive."
    H.H. Goddard, Human Efficiency (1920)

  3. #3
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    Is it better to use a quadrajet or can I use a Holley or Edelbrock carb?
    What do you mean by full dual exhaust?
    Im assuming that your saying I can get a cam up to .490 duration?
    What about lifters & rockers? Should I go flat tapper or hydraulic? Are roller rockers better or can stick be just as good?
    Thanks for all the advise Bob!!!

  4. #4
    Should I go flat tapper or hydraulic?


    i thought you didn't want to spend much money?

    you're asking for a 30hp bump ... on a 455 cube engine ( this is approx 2 tenths in a 1/4 mile ). you should be able to accomplish that by falling off a log. practically any cam swap at all should get you your goal without doing anything else.

    otoh, you said "400 HP". i suppose we should clarify what TYPE of horsepower you're looking for and if you want that at the flywheel or the rear wheel.

    the 1970 engine was rated in Gross HP ( at flywheel, no accessories, open pipe exh ). most modern dyno tests are SAE Net ( as installed with all acc. and full exh at flywheel ) or at the rear wheel, both of which give much lower numbers than Gross.

    you can see the progression in HP ratings. 1970 is 10:1 compression with Gross ratings, 71 is 8.5 compression w/Gross, 72 is 8.5 comp in SAE Net.
    70 SF == 370
    71 TA == 335
    72 WA == 260

    by comparing 71 to 72 you can see that the different ratings methodology gives you a ~22.3% lower rating vs Gross, so the 70 would be ~288 hp in more modern terminology.

    do you want 400 at the rear tires? now you have to account for losses in the trans and rear. that's a far bigger number yet at the flywheel.

    also, you get approx 5% slippage in an auto trans. change to a manual transmission and that goes away. you're also slinging less mass with a manual and they're lighter overall ( a Richmond 6 speed is just over 100 lbs ). all of which adds up to theoretically faster times in the 1/4 even though you didn't do anything to the engine.
    http://www.summitracing.com/search/b...s?autoview=SKU

    you've got to know what you're doing to get that performance out of a manual trans, though.



    Is it better to use a quadrajet or can I use a Holley or Edelbrock carb?


    you can use anything you want. Holley is probably easiest to set up and adjust. anything can be made to work.

    most experienced guys say the Quad gives better response and fuel economy when set up right. which you would expect with the tiny primaries. they're finicky though. definitely don't over torque them, it warps the throttle body and you get air bleeds around the gaskets.



    What do you mean by full dual exhaust?


    full length individual pipes from the collectors to the back of the car. most report a benefit to a crossover or H-pipe connecting the two sides in order to even the v8 exhaust pulses.

    i forgot to mention headers. you should at least put shorty headers on and get rid of the manifolds.


    oh yeah, while you're talking about engine work, no point in not decking and squaring the block to make sure you've got your 10:1 blueprinted compression. don't go beyond that though or you might start having to run 100LL AvGas to prevent pinging.


    here's the Kenne-Bell tests from back in the day.

    http://www.teambuick.com/reference/l...5_ken_bell.php

    step 6, 12 sec ET and 133mph trap calcs to ~410hp at the rear wheel and plus 500 at the flywheel.

    http://www.teambuick.com/reference/hp_calculator.php


    notice that steps 4 and 5, headers and cam are where K-B got the biggest gains.

    if you're going to do a lot of hotdogging you'll want your 200r4 built for drag strip use.
    The way to crush the bourgeoisie is to grind them between the millstones of taxation and inflation.
    Vladimir Lenin

    Government schooling is about "the perfect organization of the hive."
    H.H. Goddard, Human Efficiency (1920)

  5. #5
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    Go Quadrajet, 800 cfm. Best fuel economy and performance when built for your engine. Edelbrock has a reverse fuel curve and can end up dangerously lean at WOT on a big Buick.

    cam swap will probably put you in good shape on you hp goal. Lots of people like that TA 212 cam. Your stock heads will be fine. Stock intake is fine too, unless you want to save some weight and go to a different aluminum intake.

    Headers ra would be nice with 3" exhaust to let it flow. 2.5" might be ok for you though at your hp level.
    86 GN, all factory options, engine build in progress
    72 Skylark Convertible, 462, TH 400
    72 GSX Clone 464, TH400, 3:42. 10.71 @126mph best

    We build GM carburetors and specialize in custom built Quadrajets

    www.quadrajetpower.com
    mark@quadrajetpower.com

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