Interest in Performance Parts for slants?

Slant 6 Engines

  1. Bill Dedman

    Bill Dedman bill dedman Legendary Member

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    Thanks for the support, Sleeper, but my point was, because of the narrrow bore spacing parameters, even WITH the proper head work and the biggest valves you can stuff in there, making a deep breather out of a normally-aspirated slant six just isn't gonna happen.

    Consider this:

    The slant 6 has the same identical cylinder volume as a 302 V8 (1967 Chevy Z-28.)

    Slant over-size valves 1.75" intake/1.5" exhaust

    Chevy 302 V8 STOCK valves 2.02" intake/1.6" exhaust

    Total valve area:

    Slant: 2.40 intake + 1.77 exhaust = 4.17 sq. in. of total valve area per cylinder
    Chevy: 3.20 intake + 2.01 exhaust = 5.21 sq. in. of total valve are per cylinder

    That is a difference of TWENTY FIVE PERCENT!

    That is a comparison of a STOCK 302 Chevy (37.75 cu. in/cyl.) to a "BIG VALVE" slant six (also 37.5 cu, in./cylinder.)

    That is what valve size most people end up with in their ported slant six heads, as the largest practical head diameters for the two valves. There are offset guides available to install still larger sizes of valves, but with the 1.75" X 1.5" valves taking up 95% of the bore, installing larger diameter valves begs the question of shrouding on the combustion chamber walls and/or cylinder walls.

    Anyway, that is the problem; resitricted valve size that is dictated by the (relatively) small cylinder diameter.

    The biggest ports in the world won't help that problem. It all boils down to the weak link in the chain, which in this case, is the size valves that will fit.

    That's why aluminum cylinder heads, electronic fuel injection, roller cams and exotic intake manifolding are just band-aids on a problem that can't be fixed with bolt-ons; the only thing that will cure this lack of breathing ability is more cow bell... er, in this case, forced induction of one kind or another.

    My personal choice is turbocharging because lying on its side as it does, the slant 6 leaves a LOT of room in even the generation I A-Bodies for a turbo and plumbing, but any kind of supercharger or turbo will work well, I think, and N20 also can be used to get around the /6's breathing problems.

    But EFI on ANY kind of a N-A manifold isn't going to do it...

    Just my 2-cents...
     
  2. kittypancake

    kittypancake Well-Known Member

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    GREAT! I just read this whole post, now i'm gonna be late for work. BTW, I plan on copying Phista's setup.
     
  3. Dizzydean

    Dizzydean Well-Known Member

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    I agree with the general census. I put a 3.91 in the dart and had nothing but overheating problems with daily driver,went back to the 2.76 and made a freeway flyer that smokes quiet a bit of the competition and stays cool at 95-101. I love it. Just saying
     
  4. Bill Dedman

    Bill Dedman bill dedman Legendary Member

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    Well, I hope I didn't waste yout time AND make you late for work!

    Wouldn't t be nice to be able to mail-order that U-Bend with the necessary flanges already welded on it, for a reasonable price, say $75.00-$100.00?

    We spent $1,000.00 building our header and did all the work ourselves except for the welding and coating. I'm not even sure it will make more power than PISHTA's U-Bend setup.

    Go for it!!!:cheers:
     

    Attached Files:

  5. kittypancake

    kittypancake Well-Known Member

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    Another good idea that isn't mine!...how come there seems to be so many?
    \
     
  6. kittypancake

    kittypancake Well-Known Member

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    BTW...I made it with 3 minutes to spare!
     
  7. sleeper-oem

    sleeper-oem Well-Known Member

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    Just picked up my mini starter Bill before i go about the fun game of headers.
     
  8. Bill Dedman

    Bill Dedman bill dedman Legendary Member

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    A mini starter is a good place to start (no pun intended) but before you decide on a header design, you really should at lease LOOK at the deal PISHTA came up with. I think it will save a lot of people a lot of grief... and money!

    Good luck!!! :D
     
  9. Bill Dedman

    Bill Dedman bill dedman Legendary Member

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    I'll write faster, next time...:cheers:
     
  10. spikekid999

    spikekid999 MOPAR OR NO CAR!!!

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    would love to see a intake like this for the slants

    [​IMG]
     
  11. 65 Dartman

    65 Dartman FABO Gold Member FABO Gold Member

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    I have a triple SU set-up for the slant. I have seen some kind of adapter that bolted to this style of manifold that utilized 3 OEM Holley 1920s or Carters. It was just a short 90 elbow. I should have bookmarked where I saw it.

    [​IMG]

    (Before Leanna worked on it)
     
  12. vintagetinman

    vintagetinman Member

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    what engine did that head come from and where can i get one
     
  13. pishta

    pishta I know I'm right....

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    Just make one. That looks simple. some 1.5 EMT for the runners, Ebay intake flanges, some 2X3 rectangular tubing tying them together, cap the ends and cut your favorite carb mounting holes. It would flow at least as well as that relic.
     
  14. 805moparkid

    805moparkid Slant and AFX Guy

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    Probably by the end of next year i'll have a kit for a 6/71 and maybe a 4/71 blower, brackets and all.
     
  15. pishta

    pishta I know I'm right....

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    Would that include maybe a plate for a small M-45/60 Eaton? you can score those for $100 off a SC Buick Regal or Benz at a bone yard!
     
  16. 805moparkid

    805moparkid Slant and AFX Guy

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    i think you mean M90's and M112's. problem is both need to be blow thru, and they both need an intercooler to be worth while, hence me going the /71 route.

    and im looking for 20 psi and mid to high tens at 5% underdriven with the 6/71
     
  17. pishta

    pishta I know I'm right....

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    yup, your right. Sounds intriguing.....Looks like a weird setup anyway short of EFI. looking forward to that part!
     
  18. Zuluman

    Zuluman Well-Known Member

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    Brabus offers a V6 engine block for the Smart, with performance internals. The Triumph TR7 engine is 1/2 of the Stag V8 (as evidenced by the cross-flow head and location of the distributor). The latter was criticized as unreliable but British enthusiasts have further developed the engine and, with regular maintenance, runs reliably.

    A V12 from the slant 6 would need cross-flow heads and the relocation of the distributor - effectively, a new block and heads.
     
  19. /6 Matt

    /6 Matt 30 Degrees Crooked

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    The pic is fake. Read the whole thread to find out why.
     
  20. armyofchuckness

    armyofchuckness The Flying Valiant

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    I would be very interested in that. I love the idea of a turbo, but honestly it seems a bit above my level of wrenching without a kit. I'm currently going the n/a route with an Offy intake, Eddy 500 4bbl, an Erson 280/270 cam, ported and planed cylinder head with big valves, hardened seats, 340 springs and .100 shaved off the head. If I can get it above 200HP I'd be thrilled, but I still have my doubts I'll ever get there without a boost. I've been toying with going nitrous, but that may be more trouble than its worth for a 99.9% street car.

    Has anyone done turbo and a/c at the same time? I would think there wouldn't be clearance issues since the compressor is way up front, but I wasn't sure.

    Great thread and a lot of great ideas.
     
  21. cjh

    cjh Well-Known Member

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    Here's a V8 Caddy engine from 1929....it isn't crossflow like usual.
    The intake and exhaust is in the valley....like 3500 series CAT engine.

    http://www.secondchancegarage.com/p...-cadillac-341b/1929-Cadillac-341b-engine1.jpg
     
  22. 805moparkid

    805moparkid Slant and AFX Guy

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    im probably sitting at about 215 wheel now in my motor and that should be a solid 13 second car but havn't been able to put more time into it...

    as for the turbo manifold i just got me flanges to make some for sale, lucky for you my 73 is an A/C car as was gonna try to make it work with that! battery has to be relocated though...
     
  23. Bill Dedman

    Bill Dedman bill dedman Legendary Member

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    I think that battery re-location should be the first thing done to car that's slated for forced induction. Moving it to the trunk clears up a lot of space that can be used for a turbo, a belt-driven, centrifugal supercharger or other packaging considerations having to do with the extra hardware associated with blowers. The extra weight on the back wheels is a bonus... :D
     
  24. 805moparkid

    805moparkid Slant and AFX Guy

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    no i agree, just one of those things!
     
  25. armyofchuckness

    armyofchuckness The Flying Valiant

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    Neat. I was planning to trunk the battery anyway. Early A clearance is tough enough as it is. Looking forward to hearing more.
     
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