470-vs-482 Differences/Similarities

Discussion in 'Street/strip 400/430/455' started by Dan Gerber, Dec 5, 2017.

  1. Dan Gerber

    Dan Gerber Platinum Level Contributor

    The information regarding dimensions, part sources (i.e., BBC rods, etc) for the 470 cu in combination is readily available on the Tri-Shield web site, but I can't seem to find out much about the 482 combination (other than SBC rods).

    So, what does it take to achieve 482" with a production BBB? Bore and Stroke sizes?

    Is one size "better" than the other (disregarding the likely 1+ HP and/or Ft/Lb per cu in increase with 482")?
    Donuts & Peelouts likes this.
  2. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    More displacement, more torque. I would build the bigger engine. Both engines use the same over bore of .038 (4.350). The difference is the stroke. This is achieved by offset grinding the rod pin down to a smaller size and at the same time you are giving the pin a new center. That is what gives you the stroke increase. The BBB crank uses a 2.25” rod pin. The BBC is 2.20”. Offset grinding the pin down to BBC size gives a .05” stroke increase to 3.95 for the 470. The 482 uses SBC rod pin size of 2.10. That gives you a 4.05 stroke. I believe drop in Molnar Rods are available for both engines. Ask JW.

    Last edited: Dec 5, 2017
  3. sriley531

    sriley531 M.M.O.G.

    That's the most simple and concise explanation I've seen on this topic. Thanks for posting that Wiz!!
  4. 87GN_70GS

    87GN_70GS Well-Known Member

    Here is the latest version of the 482 from Tri Shield. Molnar 6.8 rods and Autotec 4032 alloy pistons. 20171205_211818.jpg
  5. Bluzilla

    Bluzilla a.k.a. "THE DOCTOR"

    Scott, any chance of getting a picture of the piston skirt, inside of the piston and the spec sheet on the box? Thanks.

  6. Jim Weise

    Jim Weise EFI/DIS 482

    Hi Larry,

    Here are the pics you were looking for, and the specs.

    470/482 AutoTec Pistons-



    Specs for the 470/482 AutoTec Pistons

    • 4.350 Bore
    • 4032 Material
    • 1/16 comp 3/16 oil rings
    • 1.775/1.725 Compression distance
    • 26CC dish
    • .300 deep Symmetrical valve reliefs
    • 640 G Piston 142G pin
    • .990 pin bore
    • minor bore size and CD changes are free.
    • Wire locks included
    • straight pin (no offset, runs at .003 clearance for NA applications)
    • $679/set
    Last edited: Dec 7, 2017
  7. Jim Weise

    Jim Weise EFI/DIS 482

    Speaking of the 482, the latest version of the Diamond 482 high compression is also in the building, I took a few pics of that also.



    Specs for Diamond 482 High Compression piston

    4.350 bore
    1/16 comp 3/16 oil ring standard, .043/3MM available as an option (pictured)
    2618 material
    .300 symmetrical valve reliefs - 10CC
    .990 Pin
    Standard pins and spiral locks included- standard pin weight is 185 G- 149 G H-13 pin available for and extra $136.00
    Piston weight is 600 G
    CD 1.725
    customizeable- changes are $8 for each change, per piston
    NA running clearance spec is .0045, pin offset .030 for low noise when cold
    $779.00 per set
    britt'sStage 1 and Julian like this.
  8. sriley531

    sriley531 M.M.O.G.

    SO. MUCH. WANT.....:eek::eek::eek:
    TexasT likes this.
  9. Bluzilla

    Bluzilla a.k.a. "THE DOCTOR"

    Thanks Jim! ...... They look great!

    Last edited: Dec 7, 2017
  10. BuickGSrules

    BuickGSrules Gold Level Contributor

    Got one right here ;)

    Attached Files:

  11. sriley531

    sriley531 M.M.O.G.

    Jan, that doesnt look like it'd be a good fit for your car at all. You should send it over to me immediately so I can get it out of your way.... :D;):p:rolleyes:
  12. TexasT

    TexasT Texas, where are you from

    with the pistons on the 470/482 and from the look of it the 6.8" rod length also stays the same with the difference being the size of the big end, I'm guessing the expense of offset grinding the crank would be about equal?
    the upside as I've read of going to this setup over a stock length rod and crank is the lessening of the side pressure on the cylinder wall due to the longer rods. Is there a significant increase in power(hp/torque) moving up to the 470/482 for that added expense? I'm trying to keep the idea that a larger displacement is the way I want to go but for that extra money I'm leaning back to just going .038 on the .030 block I have and having the crank polished and just assembling a 464.
    I guess my question becomes, just how much extra am I or anyone looking at to have a crank ground for the stroker? I also have read the trishield rods eliminate extra work over a BBC or 5.4l ford rod . It just seems like a lot of extra work and expense if the gains really aren't there on a street engine. I think the money would be better spent on a roller cam setup and the Ta heads to keep my budget better/lower to slip it by swmbo.
    Last edited: Dec 7, 2017
    8ad-f85 likes this.
  13. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    Jim do you have any insight regarding the piston weights for the diamond vs auto tech? I see the numbers posted but the lack of a dish has to effect the # as well.

    Also have you experimented with rolling over the sharp edges on the valve reliefs or do you leave them alone? I normally remove any sharp edges on the pistons, just curious about your thoughts on this.
    8ad-f85 likes this.
  14. 87GN_70GS

    87GN_70GS Well-Known Member

    Jim can grind your crank, but check with a local grinder to save on shipping. I have a local crank grinder who will do my offset grinding very reasonably.

    There is some advantage to the lesser side loading as Jim can speak to that. But the real benefit is for zero-decking; there will be much less work needed to zero deck a production piece setup.
  15. 87GN_70GS

    87GN_70GS Well-Known Member

    "640 G Piston 142G pin"

    "standard pin weight is 185 G- 149 G H-13 pin available for and extra $136.00
    Piston weight is 600 G"
  16. TexasT

    TexasT Texas, where are you from

    if one is getting new pistons and can select the compression height no matter which combo so to me no matter which option is selected, one will zero deck the setup. The extra comes from the crank grinding. And if one decides to forgo the new rods on a 464 to save some money.
    I'm just trying to get in my noggin, how much more it will cost and how much power increase we might see for that extra coin.
  17. Bluzilla

    Bluzilla a.k.a. "THE DOCTOR"

    I believe JW has Crankshaft Suppy in Minneapolis MN grind the offset crankshafts.

    Again.... I feel if JW uses them they must be good. I spoke with Crankshaft Supply (Roger) a while back and he was very informative and after conversation they get my vote.

    Last edited: Dec 11, 2017
    meteo7880 likes this.
  18. 8ad-f85

    8ad-f85 Well-Known Member

    Your power increases comes from the induction.
    The bore/stroke combos and how they are derived are often based on borrowing designs or parts from other platforms' having enough availability to either ease machining concerns and/or offer attributes shared by those designs.
    The stock parts are easily bested by what's out there for other brands' designs in performance parts.
    So many of these engine designs have way more beef than needed in the cranks that we can machine down dimensions to borrow parts or slightly alter existing parts and come up with more convenient stroked packages.
    They save money sometimes by eliminating related machining operations that would have previously been necessary to make it all work.
    You get performance increases when lightening things up and durability by using tougher parts than stock.
    If using a common bearing size, you now have the ability to rebuild somewhat inexpensively if needed.
    So if the question of "what's the 482 worth over the 464 power wise?" and you plan on using a stock-ish top end intended for 500 hp...the answer is minimal gains for the cost, but a much tougher engine in some regards.
  19. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    The zero deck is the most important factor I think. You should plan on that regardless of what displacement engine you build. Zero deck gives you the most efficient detonation resistant short block, and lets face it, detonation at WOT is probably what takes out a lot of engines. It is death to a BBB if you let it go unchecked, or you are not aware of it. The Pistons with altered CD get you there easier. Who wants to take .050 or more off the deck? Besides being expensive, I can't see it being good for overall block strength.
  20. TexasT

    TexasT Texas, where are you from

    with the idea that the power isn't much but the outlay of cash becomes several hundred I think the 464 with that money spent on a jw or other port job on the Ta heads for more performance for the same dollar is a better outlay for me. Others with a bigger budget might differ. I'm not into, "I've got a bigger. ....engine". I want the most power I can get to the ground for the least amount of money.
    8ad-f85 likes this.

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