455 Intake swap

Discussion in 'Street/strip 400/430/455' started by matt68gs400, Sep 12, 2018.

  1. matt68gs400

    matt68gs400 Well-Known Member

    F6C6A76C-FCD0-4056-A4AB-E6D6E4AB66DF.jpeg 13A82DA6-4016-491C-8ACC-8129458B455B.jpeg Finally getting to that intake swap.
    Nailhead Ronnie and BuickV8Mike like this.
  2. Bigpig455

    Bigpig455 Fastest of the slow....

    Be interested what kind of ET gains you might see - I have one with the plenum done just like that, I havent tried it yet
  3. matt68gs400

    matt68gs400 Well-Known Member

    Been told 8-10 hp. I hope to take it to the track in a few weeks and see if it’s measurable there.
  4. matt68gs400

    matt68gs400 Well-Known Member

    Once the black permatex is on both sides of gasket, and intake in correct position, do I torque intake bolts to 50 lb-ft. specs or do i torque part way and wait for permatex to cure?
  5. hugger

    hugger Well-Known Member

    Gasgacinch around the intake ports, rtv around water. Two stages go 25ftlbs then I believe the iron intakes are 55ftlbs. let it sit over night and break them loose 1/8 turn or so then retorque to the 55 or whatever
  6. matt68gs400

    matt68gs400 Well-Known Member

    Thank you sir. So after 25 ft lb, let it sit for a while or immediately go to 55?

    Both my help sheets leave out a few details.
  7. Rob Ross

    Rob Ross Well-Known Member

    I dyno'd this years ago, I think it was 12 hp but we left the divider the regular height. I have a stock intake where I made removable dividers and never found any gains from it. Tried full height, notch in the rear, 1/2 height and none at all. Meaning, once you make it look like a B4B, all other combos were equal.
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  8. matt68gs400

    matt68gs400 Well-Known Member

    I’ll take that extra 4 HP!
  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    No, after 25, go right to 55.
    matt68gs400 likes this.
  10. No Lift

    No Lift Platinum Level Contributor

    Once you get to 25 ft. lbs with a steel shim gasket the Permatex won't know the difference when you step up to 55. Crushed is crushed and probably after 10 ft. lbs. the gasket doesn't crush any more. Not saying don't take it to 55, just saying the Permatex doesn't know the difference.
    matt68gs400 likes this.
  11. matt68gs400

    matt68gs400 Well-Known Member

    No Gaskacinch locally and want to do this tonight so I bought some Permatex Indianhead gasket shellac. Supposed to be similar.
  12. matt68gs400

    matt68gs400 Well-Known Member

    I see what you mean, thanks!
  13. Schurkey

    Schurkey Silver Level contributor

    Both are gasket sealers. No, they're not similar.

    Indianhead dries hard. Gasgacinch dries "rubbery". (Gasgacinch is liquid neoprene.)

    Is that center divider ground to a knife-edge? That's how it looks on my screen. Ideally, that divider would have a rounded but blunt top edge, not thin and "sharp".
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  14. buicksstage1

    buicksstage1 Well-Known Member

    High Tack is best on steel shim around the ports and cone on water. Spray both sides of the gaskey and the heads and intake surfaces. They use to put a small tube and a brush in the box with the gasket.
  15. matt68gs400

    matt68gs400 Well-Known Member

    I’d say it’s thinner but not a knife edge. It’s not sharp at all. Its has a rounded top. It’s also not a very blunt bull nose either.
  16. matt68gs400

    matt68gs400 Well-Known Member

    Is the Copper coat spray equivalent to the High tack spray?
  17. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

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  18. Schurkey

    Schurkey Silver Level contributor

    High Tack, Copper Coat, Gasgacinch, Hylomar...there's at least a dozen comparable gasket sealers. I've used Permatex pipe thread sealer with Teflon, in the big brush-top tubs on gaskets with good success.

    I quit using Weatherstrip Adhesive (Yellow Death) and I've quit using RTV silicone as gasket sealers. Yellow Death is too hard to clean-up the next time you take it apart; and silicone on gaskets just promotes sliding out-of-position during assembly; along with blobs of silicone sealer in the coolant, or worse, in the oil system.

    The only RTV silicone I use is INSTEAD of a gasket, not as a gasket supplement. That, and a dot of RTV on the seam between two gaskets, or the joint between a gasket and a rubber seal. Truth to be told, when there's a pair of "hard" castings (not a stamped-sheetmetal joint like an oil pan-to-block, or valve covers-to-head, Permatex anaerobic gasket maker (518) works better than RTV.

    I happen to have a brush-top can of High Tack in the shop right now...but when that runs out, I'll probably go back to Gasgacinch. Gasgacinch does almost everything Hylomar does, at 1/10 the cost, and with very easy clean-up the next time it comes apart.

    We used a lot of Permatex non-hardening gasket sealer (#2) at work. Messy, but effective.

    I've heard good things about The Right Stuff, which as I understand is urethane not RTV silicone. Just like silicone, I'd be more likely to use it instead of a gasket than on a gasket.
    Last edited: Sep 14, 2018
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  19. 41speciman

    41speciman Well-Known Member

    The right stuff sticks good and hard to get apart when need to
  20. BuickV8Mike

    BuickV8Mike SD Buick Fan

    Schurkey, What happened to the second best Avatar on the board? ;) He was the guy from Reno 911. Can you share what happened with Net Neutral ity ? I'm some we all lost.... Are we cutting hairs here with the edge configuration of the divider? Don,t make start looking up Reynolds numbers.:) I love your posts, what do you do?

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