Is the TA Performance 308S the Best Solid Flat Tappet cam to use Street/Strip

Discussion in 'Street/strip 400/430/455' started by Rossco Mason, Apr 21, 2017.

  1. Bens99gtp

    Bens99gtp Well-Known Member

    We have an iron headed 464, stk rods, je piston, sitting 030 in the hole (machine shop error in not understanding what is the differance between 10 in hoke and 10 off the deck) but we are just under 11.2 compression with an 027 headgasket. Car and drive is 3850 running a 308s cam and we have run a best time of 10.90s (no spray on our car) we run 6500 rpm regularly and have seen over 2200 passes on stk rods. Our new motor will be more compression, molnar rods, and cnc track 2 heads.

    I like the 308s but it only pulls about 4 inches of vaccum in my car with a lock out distributor and 900 rpm idle.....so make sure you see how the efi takes into account the MAP cause low vac could cause issues there.....and it won't run power brakes on the street without some form of vaccum pump assistance.
     
  2. slimfromnz

    slimfromnz Kiwi Abroad

    It feels great driving around an LS2 turbo car over the 1/8 mile lol
     
  3. LARRY70GS

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

    I didn't machine anything, the machinist that JW used did that. :D And yes, the Molnar rods are drop in now, but my engine was built 5 years ago. All this is described by JW, http://www.trishieldperformance.com/470--what-and-why-.html
     
    Last edited: Apr 23, 2017
    Rossco Mason likes this.
  4. Jim Weise

    Jim Weise EFI/DIS 482

    Rossco,

    All my Molnar rods are 6.800 in length.

    Yes, when I built Larry's engine (and many others) we had to widen the crank throws to 2". This was eliminated when we went to the custom Buick rod, vs the BBC rod.

    Yes, .020 deck cut is all that is required for any 470/482 combo

    JW
     
  5. Rossco Mason

    Rossco Mason Active Member

    Hi Jim, Been away for a few days it was Anzac Day over here so respected the fallen soldiers from both wars a little hungover.

    I had a chat with Neil my Engine builder he likes that Hydrualic Roller cam 243/260@ .050 .611/.594 lift with a LSA 112 installed @ 108 and it has 12 inches of vacuum, this engine will be Dyno'd so like Neil said he will play with the cam installation to see what works better @ 106 or 108 will get it on the Dyno to get the right setup.

    Is it easier getting that Hydraulic Roller Cam TA Roller Lifters & 1.65 Rollers push rods cam button etc through Tri-Shield or TA.

    We also had a good chat on the strokes he seems to like the 470ci setup .050 off the crank is nice .150 is a little to much in his eyes so thats the way we look like going.
    I do need the Compression @ 11.5:1
    Our moddo is build it once and freshen it up ever 10yrs & drive it like you stole it
     
  6. Rossco Mason

    Rossco Mason Active Member

    They last 5 mins "The LS BOOM"
    If you spend 20k may last a little longer.
     
  7. Jim Weise

    Jim Weise EFI/DIS 482

    Rossco,

    Assuming Chris Skaling got that cam from Scott Brown, you better call/email him and get the exact same one.

    To maintain anywhere near that vacuum from a cam with those specs at a reasonable idle speed, the advertised duration has to be in the low 290's for the intake lobe, and the ramps extremely fast. Most cam grinders will tell you that the Buick journal size/Base circle is too small for that lobe speed. Certainly, there will be a serious requirement for increased spring pressure, and combined with a high ratio rocker, your simply asking for lifter failure and rpm limitations. At the very least, your looking at questionable long term engine component life, due to the higher stresses.

    I don't believe in fast ramp hydraulic/hydraulic roller camshafts. If your looking for aggressive ramp speed, and since your already installing a lifter bore girdle, step up to a solid roller camshaft. Select solid roller lobe which requires less than 600 lbs on the nose, and you should experience reasonable service life of the camshaft.

    I would be happy to work with you for a solid roller cam to achieve your goals.

    JW
     
  8. Rossco Mason

    Rossco Mason Active Member

    A Solid Roller what Spring pressures would we be looking at Jim

    I was alway under the impression the reason for using the Hyraulic Roller was because the Spring pressure wasnt as high like the Solid Roller.
    The Hydraulic Roller losers top end power at high revs and the Solid keeps going i understand all that lifter flutter ect, but the reason we liked the Hydraulic was it made good power and maintenance friendly no adjusting rollers and lower spring pressures.

    Neil prefers a Solid Flat Tappet thats why we have been looking at the 308S but with the Stage 2 SE heads the 304S would work better, so i feel like i have gone back to the drawing board.

    When i read the Forum on the Hydraulic Roller it sounded very positive, it really did make us look at that setup with the 470ci, remember i still want to drive it on the street more hiway than anything due to where i live. That's why i will be using a Gear Vendor.
    So with what we want to use this car for is a solid roller the way to go maybe a solid Flat Tappet or Hydraulic Roller, there are a lot of cars over here running 650+hp and they are very streetable.

    Over here we usually build SBC BBC ford & LS crap, so what i am trying to say is the basics on engine building are there on most engines, but Buicks are a little different so at the end of the day who do i listen to and what do i use, pretty much 100% on what where building using the 470ci setup 11.5:1 comp stg2 SE heads will flow over 350cfm not a prob there, SP1 manifold ported right and Burr ported inside, using a FiTech EFI 1200hp setup the only thing we cant decide on is a cam.
    So what cam should we us?

    Rossco
     
    Last edited: Apr 27, 2017
  9. Rossco Mason

    Rossco Mason Active Member

    What's the best street/strip combo that you have seen running a 470ci with Stg2 SE heads Jim

    Rossco
     
  10. Jim Weise

    Jim Weise EFI/DIS 482

    I think a Hydraulic roller with a more conventional lobe on it, with generous specs and a wider lobe center would actually work out nicely for you. And not beat up the valvetrain in the process. Something along the lines of a 245/250/114. That cam has 19.5* of overlap, gets the Intake valve closed around 50* for good vacuum, yet has enough duration to make power. You can play with it's installed location, but I would suggest you start at 108.. and move it 2* at a time back toward zero advance, until you find the best combo of power, idle quality and vacuum.

    My point above was if your going with a fast ramp hyd roller, you might as well just go with a small solid. Required valve spring pressure for an aggressive hyd roller, and a small solid are not that much different. The solid will be even faster off and on the seat, and will retain more vacuum, and you won't be beating up a hydrulic lifter, or be rpm limited.

    I would certainly not recommend a 308 or 304 flat tappet cam for street use.. those cams, while they work great above 4500 rpm, lack the kind of mid range torque you want for a street driver, and have horrible idle manners, and very little vacuum.

    Here is a dyno sheet of a motor I built, with specs very similar to yours, with a 240/244/114 hyd roller.

    [​IMG]
     
    Julian likes this.
  11. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Nice build Jim!

    After seeing that dyno sheet it got me wondering what those numbers would look like if all things were the same except one being a 470 and the other being a 482.
    Do you have a dyno comparison of basically the same engine with the same cam, heads and intake except one being a 470 and the other being a 482? If anyone had that comparison I would think it would be you, curious mind wants to know, thanks.

    Derek
     
  12. Rossco Mason

    Rossco Mason Active Member

    Hi Jim,
    Now that sounds excellent, i thought going with the 308s or 304s felt like going back 20yrs ago need something i can drive and enjoy that makes good power like that Dyno chart. That sounds excellent to me Jim if i can make that hp with the 470ci setup SE heads etc i will be a very happy man.

    I have a good mate with a 65 Mustang with a Procharged Windsor making around 700hp and really its not streetable its running E85 has 5500 converter just not my cup of tea, this 470ci engine with FiTech EFI will run on 98octane which we have on pump gas so 11.5:1 with the efi & the Hydraulic roller setup will not only make good HP it should be very streetable just what i am looking for, you got me.

    You said earlier you use the same 6.800 rods for the 470 & 482ci so machining the crank .150 that means you use a different height piston to change the stroke.
    How much extra stress machining .150 off the journal does it have.
    If i am using a Mains Girdle that wouldn't be a problem with flex or stress at 6500 RPM's
    Like that Post above what would i see between 470 and 482ci in hp & Tq

    Rossco
     
  13. LARRY70GS

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

    No, the stroke is changed by offset grinding the rod journal. What you are doing is giving that rod journal a new center at the same time that you are reducing it's diameter. That is what changes the stroke. The piston compression height (measured from the piston pin center to the top of the piston) is what determines where the piston sits at TDC, how far down the cylinder. You want zero deck, the piston top is even with the block deck at TDC.
     
    Rossco Mason likes this.
  14. Rossco Mason

    Rossco Mason Active Member

    How are you Larry,
    I got that now, didn't realise from 470 to 482 (12cubes ) .100 off the crank can change that much, so it ends up with 2.100 on the journal.
    So they hold up not a problem no stress or flex?

    Rossco
     
  15. Jim Weise

    Jim Weise EFI/DIS 482

    I should be more clear on the dyno sheet I showed.. I wanted to throw up something with similar airflow heads and compression to what your talking about, with a cam I am talking about, to show you that it can make the power your after. I did not have a lot of time to discuss what it was actually this morning, and I just got in right now from the shop... the point was you don't need some wild ass fast ramp cam with 17 degrees more exhaust than intake to make that power.

    That particular motor had 35oish cfm early CNC port TA Stage 2 TE heads on it, 11.2 compression and it's a 494... so it has the 2" rod journals on it.. and there is no issue with crank failure. I have run over 1100 HP thru a stock Buick crank and not broken it. 700 to 800 HP 494's are pretty common in the Buick racing world, and there is no rash of crank failures.. it's typically the same old story, the block fails..

    Don't get all caught up with the cubic inches.. there are many racers on this board that can tell you that they broke the block or something on their 494 race motor, and threw together a high compression 464ci shortblock, bolted on all their go fast goodies, and took the car out and ran the exact same ET and MPH as the 494.

    Because fundamentally, all Buicks are cylinder head limited. The math equation assumes that you have the ability to flow the extra air the bigger motor wants, but that's not typically the case. The cylinder heads are dictating power output, not the size of the pump below them.

    You may notice that this cam is actually 1 step smaller than the one I suggested for you. The bigger cam, along with 360- 370ish SE heads if your guy can get them there, should put your 470 in the 650+ HP zone you want to be in.

    Yet still be streetable, and not beating up the valvetrain.
     
  16. Rossco Mason

    Rossco Mason Active Member

    Hi Jim,
    Thank for your time much appreciated, that has explained heaps and pointed us in the right direction.

    So our main thing is now for Neil to complete these heads and see how much CFM he can get out of them and go from there, after speaking again today he seems to think it will be achievable for around 360 or more Cfm.

    You said the blocks seem to let the HP down, when using both Girdles that should strengthen the block to the point were I shouldn't have to much trouble making that kind of HP.

    Like the Hydraulic Roller cam setup for the street and should work nicely on the strip 245/250 /114 @ 108 then we shall have a play on the dyno to see where she likes to be.

    I have a few things to sell and then i will be ordering the parts required for the build.

    Rossco
     
  17. slimfromnz

    slimfromnz Kiwi Abroad

    How is everything going mate?
    The girdles will certainly help keep your rotating mass together. Once you drive this beast, you wont see the need for 6000+rpm much, unless the hides are smoking!!!
    We are racing the rod at Willowbank Easter weekend if youre around.
    Cheers
     
  18. NZ GS 400

    NZ GS 400 Gold Level Contributor

    Hey Rossco, I am not sure where you are located. I think NZ? You probably already know this, but just a reminder that USA octane calculations are different from the ones we use here in NZ. Hopefully this may help you.
     
    slimfromnz likes this.

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