High Performance Nailheads

Discussion in ''Da Nailhead' started by funkyriv, Jan 28, 2008.

  1. funkyriv

    funkyriv Well-Known Member

    Hello!
    After scanning the threads in the Nailhead forum plus some online searching I was unable to come up with clear ideas on how to make a 425cid nailhead engine into a 500+ HP monster. Think like you wanted a 12-13 sec 64-66 riviera, or 10-11 sec skylark from that era. Private correspondence with Tom Telesco seemed to indicate that one might be able to achieve 400+ (maybe 440) with the 425, but it would be expensive and time consuming. Perhaps a similar investment (time and money) would produce a 455cid with 550HP.

    From expert opinion (not mine - i'm no expert!) the biggest performance increase for the nailhead engine will come from extensive head modifications (porting, rockers, and valves), but this is also very expensive if done right. What about intakes, carbs, pistons, etc. What are the incremental performance improvements one can expect to see with nailhead modifications? If you want 500HP should you just punt the nailhead for other engine options (455, LS2).

    Thanks!
    Bert

    modification-------HP gain------------cost
    carb/intake --------20HP
    Etc.
    Etc.
     
  2. flynbuick

    flynbuick Super Moderator Staff Member

    The problem with your premise is the changes are not generally additive for horsepower gains in the way you invite for any engine. I think Bob Quigg has the quickest full A body naturally aspirated nailhead at 11.64 115.88 mph. So I think you can see why a Riv weighing maybe 1000 lbs more than Bob's car is going to be considerably slower than his numbers.
     
  3. funkyriv

    funkyriv Well-Known Member

    Very true, i get your point on the non-additive gains in HP; this depends very much on the specific parts used in the mods and the sequence of the mods. What if we constrain the possibilities by assuming that the modifications were done starting with the easiest mods and working up to the more difficult mods? (Of course I don't want to spark a debate on what is easiest vs. hardest mod for engine building - changing carb seems easy, changing pistons is more work/harder.)

    Thx!
     
  4. GranSportSedan

    GranSportSedan Puppet dictator, wife has all power

    The 401/425 is a great foundation for using a centrifugal supercharger and that is a great way to make 500-600 very streetable horsepower. nobody would ever suspect a thing unless you opened the hood.
     
  5. nekkidhillbilly

    nekkidhillbilly post whore

    turbos and efi would make it easy
     
  6. telriv

    telriv Well-Known Member

    As of 11/05 the new times are 11.08ET @ 122MPH with no traction may I add!!!!!

    Tom T.
     
  7. doc

    doc Well-Known Member

    Which nail head would win a drag race, one that will get 425 hp in 10 sec or one that will get 425hp is 3 sec.???????? Most mods dont add that much hp they just make an engine get what it has a lot quicker.
     
  8. funkyriv

    funkyriv Well-Known Member

    Is there a resource that can provide more information on sources and specs for this supercharger option and the other modifications required to build it? So far the only nailhead superchargers that i've seen require hardware extending through the top of the engine hood.
     
  9. jimtash

    jimtash Well-Known Member

    Yep. It applies to weight as well. My '63 Riv weighs so much that the mechanic I take it to says the lift comes down very quick whenever it's on it compared to other cars. So with that in mind, I can't expect it to be fast no matter what mods I try to do the engine.
     
  10. flynbuick

    flynbuick Super Moderator Staff Member



    In the 63 model you have a trans limitation.
     
  11. funkyriv

    funkyriv Well-Known Member

    Is there a resource that can provide more information on sources and specs for nailhead turbo/EFI and the other modifications required for the set-up? Thx!
     
  12. flynbuick

    flynbuick Super Moderator Staff Member



    Here is my all time favorite that they have now converted to FI.


    Hilborn

    http://www.hilborninjection.com/product.asp?Id=379&CatId=167
     
  13. jimtash

    jimtash Well-Known Member

    True but weight reduction goes a long way, even in a Dynaflow equipped car. And the best part about it, it's free.
     
  14. yacster

    yacster Lv the gun tk the Canolis

    Tom - How many carbide burrs and die grinders were killed in the making of those numbers above? :grin: I guess porting the hell out of the heads and many other little tricks you guys have learned from the many hours of R&D have payed off. Besides the roller rockers which we know are awsome, is there an easy way for the backyard mechanic to pull more power out of a naturally asperated nail. I remember a while ago Mopar used to put out a kit which would allow you to grind the heads with the aid of a template and give you the measurments for the valves to better flow the 440 heads. After a weekend of work you would add some serious HP & Torque #'s. I know Greg Gessler does this to make a living but I am sure if he put a kit like that together for $200.00 or so bucks, he could make a lot more $$ and help the back yard boys out.
    Other than that, a lot of us really don't see performance bolt ons other than nitrous, turbos and huffers. What's a nailhead nut to do??:Do No:
     
  15. ahhh65riv

    ahhh65riv Well-Known Member

    I'm not using any of those things (Nitrous, Turbo, or a "huffer"), but I can tell you it's not cheap, and you aren't going to find it in a Jegs or Summit Catalog. You do it just like they used to do back in the day. Many of those secrets are either lost or forgotten by the teams of many racing legends like Mickey Thompson, Don Garlitz and of course Tommy Ivo. We should be squeezing them!

    (Anxiously waiting dyno time)
    Erik
     
  16. yacster

    yacster Lv the gun tk the Canolis

    Erik - I have a couple black pillow cases and some handcuffs, If you can supply the van and a place to hold hostages we can pick them up and make them write down everything they know about nailheads:grin: We can grab Vic Edelbrock too make him bring back the B262, and make some Alum Heads :laugh:

    I can't wait to see your #'s
     
  17. ahhh65riv

    ahhh65riv Well-Known Member

    ROTFL! Count me in!:laugh:
     
  18. nekkidhillbilly

    nekkidhillbilly post whore

    it would be an all custom setup that you would have to fabircate but could be done . if you know anything about turbos or efis it would be somethin that wouldnt be all that complicated. ive posted how to build an efi setup basically as for turbos well its more or less plumbing exhaust and intake lines. i dont know how well a nail would do under boost but it would benifit if you didnt overdue it and blow it up.
     
  19. nekkidhillbilly

    nekkidhillbilly post whore

    well with fab work you dont
     
  20. nekkidhillbilly

    nekkidhillbilly post whore

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