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The 351W Long-Rod Thread of Doom.

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  • merc91
    replied
    very familiar with the physics behind a longrod, I even built 1 for a guy dead set on it, and they are a waste of time and money... just like everyones opinion that has seriously built 1 and measured the gains (not just saying it revs quicker)... the reason they work best with shatty flowing heads is because its a modification that works against flowing more air through the motor at the benefit of netting a small gain in compression ceiling... decreasing piston speed at the top of the stroke helps timing/compression limits very little, but the reduced pressure wave hurts exhaust flow significantly and intake flow is hurt with slower piston speeds in the beginning of the stroke.
    It's a very very small gain in net (usable ceiling) compression/ timing as the longrods physics allowing more compression benefits exponentially based on rpm only... detonation suseptability peaks at peak VE (peak tq), where longrods benefits are not yet available. Doesn't matter how high you increase compression availability above max VE if it doesn't increase at peak VE. Gains on the adready good 302 are around 1/4 comp point and 2* timing... new piston designs will out do that without hurting the engines flow potentials (hp)
    The rotating assembly is no more efficient, yes acceleration is decreased at the top and bottom of strokes, but increased in the mid stroke (piston still travels the same distance in the same amount of time) so all the ballence/faster revving comments are just like the 3" exhaust tips adding a little more passing power lol.
    Ford made the windsors as longrods to start with, adding a few 10ths of an inch changes the numbers 1-2% depending on if you go to "crazy long" chevy rod work.

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  • Mercracer
    replied
    You are missing something...

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  • merc91
    replied
    am I missing something or does this just a way to net a little gain in compression ratio and add a tad of rotating mass?

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  • 1987cp
    replied
    There are those who say not to worry about rod length .... (see my previous post or two)


    For shortblocks and parts, you might try www.fordstrokers.com.
    Last edited by 1987cp; 07-25-2011, 08:03 AM.

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  • 85ltd
    replied
    I know this thread has been dead for quite a while, but I am curious as to where you buy a 351w long rod kit at now? All of the previous links are no longer working, and when I google it, I find nothing except talk about it being done. JUst wondering, thanks.

    Blane

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  • import convert
    replied
    would a federal mogul zh146cl work? my bad found out it needs to be for a 3" stroke
    Last edited by import convert; 08-17-2010, 12:30 AM.

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  • import convert
    replied
    any news on the long rod 302 pistons

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  • Pirate
    Guest replied
    Originally posted by 1987cp View Post
    From a thread your sworn personal enemies were posting in ...

    Thoughts? If this is correct, it sounds in short like you're spot on doing long rods with factory heads, but at what point is the cost and hassle of the longrod parts more than that of good heads?
    No matter what I do, I'm going to have to do something with a short block, in that I don't have one. I can go with the long-rod rotating assembly, use my existing P heads, and shoot for 400/400 with this combo (optimistic)....which is around what a 2005-2006 GTO was putting out...and they're a blast to drive.

    Or....I build a 408, and spend an additional $1000-$1500, and get aluminum heads, along with a bigger intake....and make around 500/500....and have trouble getting it to hook up.

    If I go the 351w-based block route....these are my two options. To be honest the 'smooth' option of the long-rod motor looks great right now (not to mention it's cheaper, and the car won't exactly be slow with the 351W), however, the nasty 408W also looks like a winnah....

    And then of course, I see this:

    Last edited by ; 07-14-2010, 01:05 PM.

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  • 1987cp
    replied
    Originally posted by The Auntie Christ View Post
    Revisiting this thread.....

    I'm curious what a 351W long-rod motor (I'm still looking for an F4 351W block, there's a bare block at my NAPA machine shop, he's wanting to sell it, but I haven't gotten a price yet) would do with prepped P heads, long-tube headers, 10:1 compression, a Comp XE258HR cam, and EFI....I'm feeling really cheap right now.


    From a thread your sworn personal enemies were posting in ...

    [Smokey Yunick] benefit[ted] from the longer rod because the cylinder heads of the day weren't as good as today. Meaning the longer rod helped limited flowing cylinder heads... Todays cylinder head designs are so much better that the long rod no longer beneficial
    Thoughts? If this is correct, it sounds in short like you're spot on doing long rods with factory heads, but at what point is the cost and hassle of the longrod parts more than that of good heads?

    Leave a comment:


  • 1990LTD
    replied
    http://capebreton.kijiji.ca/c-cars-v...AdIdZ216288624

    i'll buy it if you don't want it if it's useless, for 60 bucks I could use it as a coffee table, top gear style.

    is it useless?

    Leave a comment:


  • Pirate
    Guest replied
    Revisiting this thread.....

    I'm curious what a 351W long-rod motor (I'm still looking for an F4 351W block, there's a bare block at my NAPA machine shop, he's wanting to sell it, but I haven't gotten a price yet) would do with prepped P heads, long-tube headers, 10:1 compression, a Comp XE258HR cam, and EFI....I'm feeling really cheap right now.

    Leave a comment:


  • Pirate
    Guest replied
    Update: Wayne's engines no longer sells the modified 400 long-rods. However, Speedomotive sells a long-rod rotating assembly for the 351W, AND 351C. The issue with the 351W kit is that it comes with Hypereutectic pistons, but after speaking with them, you are allowed to substitute 331 stroker forged units (same pin compression height).

    The 351C kit is actually pretty badass, as it includes a destroked 351C crank, down from 3.5" to 3.4", and with a .030 overbore, it becomes a 346" motor, with 6.250" rods vs. 5.755 (or whatever the stock 351C rod length is, it's around 5.7", just like small-block chevys). This would make a damn-nice motor to use with a set of 2V Aussie heads, or Edelbrock 351C 2V units, and makes an interesting alternative to a 347 stroker.

    If I didn't have engine brackets that needed the windsor-based equipment, I'd really love to build that long-rod Cleveland....but the other thing scaring me off is the stock Cleveland block; it has a nightmare of an oiling system, and you have to find one that isn't bored .030 over. Otherwise, it's a snappy engine....I know, I've owned a few Cleveland-powered cars, and built or worked on several others.

    More later.

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  • Pirate
    Guest replied
    Originally posted by Pirate View Post
    Howdy, gang.....

    I have some more 302 long-rod information handy.....and have located forged pistons for this setup.

    http://www.kb-silvolite.com/feature....n=read&F_id=21

    Of interest is the KB747; it's for a stock stroke 302, with 5.4 rods. In addition, it produces 10.6:1 compression with 64 CC heads....with a little smoothing of the dome, this piston, coupled with a 5.4 rod, should let you get away with around 10:1 compression with either E7 heads, or regular GT40 units.
    Update: United Engine Machine, the makers of KB pistons, have re-done their website, and the forged long-rod pistons for the 302 are no longer listed. However, I don't know if they have been discontinued, or are merely still working on the site, as some links pop up with a 'still under construction' page....

    I'm working on finding a similar compression-height piston to use in its place, but I've only found one site that has had the KB747 piston still listed, and includes the compression height.

    More to follow later....

    Leave a comment:


  • CheeseSteakJim
    replied
    That's not too bad. I'm going to keep these dudes in mind.

    Leave a comment:


  • Pirate
    Guest replied
    http://waynesengines.com/index.htm

    The site is back up....these are the guys that sell modded 5.565 Chevy 400 rods for 302's, and modded 400 Ford rods for 351W's....prices are around $275-$300 for a set of rods.

    Leave a comment:

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