500rwhp the real limit?

Discussion in 'Fox 5.0 Mustang Tech' started by dubbsix, Jan 6, 2007.


  1. dubbsix

    dubbsix Member

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    Well i have read all over the boards that anymore than 500rwhp and you are running on borrowed time. Some have even posted pics of blocks split in half. Now my question is if there is a theoretical limit of 500 to the wheels, then why do we see so many combos in mustang magazines that are putting down over 500HP reliablly on stock blocks?
  2. 86bluecobra

    86bluecobra Advanced Member

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    Well i would say the reason why you see mags doing articles on 500hp ponies is because now people can get 500 ponies. It used to be the magic number was 400 ponies that they were shooting for. As for reliable 500 hp well any car pushing that on some what stock parts is not really building a reliable engine. The fact of the matter is the factory block is only good for so much power. Push it beyond its design and you can expect a breakage. Also it depends on how you drive. If you had 500 ponies but drove like a little old lady i bet you would never split a block however if you drive like most of us 5.0L guys its just a matter of time.


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  3. dubbsix

    dubbsix Member

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    I understand. I understand that to build a reliable motor that can hit 500HP you will probably need to go with aftermarket parts, but i have seen so many articles where daily driven 5-0's are pushing 500 or more on a stock 302 block with after market internals. Just wanted some concrete opinions on the strength of the 302
  4. RS200

    RS200 Member

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    At 500whp, it's all in the tune to keep it right. If anything's off, the block is done. That being said, I've seen 630whp stock block. There's a tradeoff in RPM vs power..high winding engine under 500hp will last a long time. Same for 500hp kept under 6000. Also, the braces are pretty much useless. Sure, get them..they'll keep the block all tidy if it blows. Do it right or you WILL do it again.
  5. bentley429

    bentley429 Banned

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    The reason you see so many stock block 500 hp+ cars is because they can. Iam personally building a setup that should be able to see close to if not 500 but Iam not going to run that much boost to get the power at a reasonable level for the block. 425 or so is what Iam aiming for which should make for a reliable fun car that I dont really have to worry about.
  6. poneypower89

    poneypower89 Now everyone in the world will know I wanna bang t

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    retarded double post... ugh
  7. poneypower89

    poneypower89 Now everyone in the world will know I wanna bang t

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    I doesn't make sense to me that you see stock blocks built with aftermarket internals to hold 500hp.... considering the stock internals are actually stronger than the stock block :rolleyes: Kinda counter intuitive. (only exception there being that they only have aftermarket internals to achieve a stroker combination).

    I'm willing to bet a lot of the combos you see posting those numbers either

    A) dont actually have a stock block (maybe mexican or aftermarket)

    B) Aren't driven that much or that hard.

    C) Are posting that 500hp with the use of Nitrous (which means they aren't in block cracking territory normally)

    D) Are scared because they know EVENTUALLY all their hard work is gonna end up on the ground in a puddle of oil, coolant, and metal shavings... :rolleyes:
  8. seijirou

    seijirou Founding Member

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    Realistically, you don't see that many cars doing it.
    Out of all the hundreds of thousands of 5.0 blocks produced, you might see maybe 50.. maybe 100 throughout all the magazines of daily driven 500hp 302s.
    What you don't see in the magazines are all the other thousands of guys who have put that power into their blocks, and subsequently blew that power all over the asphault.

    It is possible to put 500rwhp through a stock block and drive it everyday and not have it blow, but it's also possible to win big in the lottery.

    Just keep it in perspective.

    If you want that much power, and who doesn't, you're much wiser to go with a stronger block. Even the cheapest of aftermarket blocks will do 500hp all day long. :nice:
  9. bubba-dough

    bubba-dough Active Member

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    If you had the money to build 500 rwhp why would you settle for a stock block. The thinking behind it makes absolutely no sense to me. If I were dumping thousands upon thousands of dollars into an engine to achieve those kinds of numbers there is no way I chance all of my money, time and life into something that is on the brink of disaster. Potentially losing everything because chances are the parts will not be salvagable.

    Those magazine ones are probably guys who thought "hey lets get in a mag by building a 500 rwhp stock block Mustang". They do this with no thought of ever really driving it or keeping it that way. Its just to say look what we did and we got in a mag. ("Now lets tear her down and do it right").

    As for limits there is a design theory of the block. There are also real world results. There are a lot of variables that go into how liong the block will last.

    That said, my pal put down 368 rwhp and 400 rwtq. We then threw on a 125 shot. I would say that, that was awfully close to 500 rwhp and definately over 500 rwtq. He drove it like he stole it, spraying the crap out of it. Wanting to see what it could handle because he already had the funds for the new set-up (which is a dart block stroker). The mainshaft in the tranny blew not the engine. But like said above, that extra 125 wasn't there all the time:shrug:
  10. dubbsix

    dubbsix Member

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    Well i agree with most of you that when you get close to or over 500 its time to invest in an aftermarket block. The point of the post was to have every one give their two cents about why so frequently are stock block mustangs running over 500HP.

    The mags usually do a pretty good job of laying out the internals and specs of the cars, and i would say that 90% of the cars that reach 500HP are blown.. not nitrous whores.
  11. 347blown

    347blown New Member

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    Hey guys: ok i finished putting together my combo and brought it to the dyno and got 500 rwhp, i still didn't finish the tune started loosing fuel volume, also didn't get a chance to spray the methanol injection and that was at 4500 rpm and 12.5 fuel ratio, yeah i know i am on borrowed time, so what u would do if u were in my shoes? got a 347 with a s trim making 15lbs of boost, Thinking of lowering the boost? Or Yank everything and putting in another block? Also got the crank girdle
  12. seijirou

    seijirou Founding Member

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    347: depends on your budget man, it's good that you're getting a tune. The better the tune the longer it will live, you may want to consider backing it out some to be safe, or if you have the money for it get yourself a new block to build. The girdle isn't really going to do anything for strength. There are products such as block fillers you can look into, altho I cannot speak for how they work. Something like that also depends on how much/what kind of use the car is going to see.


    Again, I really feel like the word 'frequently' is misused here. The "mag" cars are a very small portion of the percentage of the people out there who build cars. Also there are more untouched 302s out there than there are modified ones.

    So what you're talking about a percentage of a group which is already a percentage of another group. A piece of a piece of the pie.

    This is a very small sampling of 302s that are pulling this off, your magazines are not documenting all the guys with exploded engines. I would bet money in the real world there are more failure stories than success ones.

    Frequent is not the right word, maybe it's common in a magazine, but as much as I wish it weren't true the fact is the magazines are borderline fantasyland and really resemble tabloids somtimes. I wonder if they don't do more harm than good, but that's a rant for another time.
  13. RS200

    RS200 Member

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    Eek..347? That's major sideload on cylinders. Big hp on the stock block should be stock stroke and bore, probably with a longrod setup.
  14. wicked84gt350

    wicked84gt350 New Member

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    The thing that dictates how much power it will handle is the seasoning and the intrenal balancing of the motor. To really have a good seanoned block it needs to have at least 100,000 miles on it. That is the popularly agreed milage. then the internals need to be balanced because nothing kills blocks and parts like vibration and a good machining job bore, balance, deck and believe it or not boiling out the block helps seanson the block mine has been boiled twice. And the 500 rwhp is just a estimation unless its a mexican block which is really strong but the 500 is really only bependant if you are running boost or spray. which putts a lot of stress on the block a lot more than just n/a. The n/a motor if you can get the numbers out of such small inches will probally with a deacent tune last a good long time at 500rwhp.
  15. dubbsix

    dubbsix Member

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    Sounds like a block living with 500HP is more realistic than we admit to. I said it earlier and i'll say it again: If your shooting for the 500 mark then you may as well invest in good internal parts and machine work. But given those things it can be done.. and run without fearing pending explosion.
  16. wicked84gt350

    wicked84gt350 New Member

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    You know, now that I tally some of the cost for machining and internals I would almost be adventagious to buy a dss or a aftermarket block. I have 200 in the bore, 550 in parrell deck and balance, 100 in boiling, 150 in bolts, 350 in rods and hyper pistons and another 80 in crank poleshing and another 200 in balancer so were are in the 1600 range which is a aftermarket block but the thing is I have a block almost as strong as a aftermarket and I got all the internals with that cost But I am sure I am missing some cost along the way you start to loose track after a while but it is good enough for what I am going to accomplish with this motor.
  17. millhouse

    millhouse Founding Member

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    If you plan on pushing 450+ rwhp on a regular basis...plan on breakage plain and simple. It's really a crap shoot for us at those levels. Some have pushed 600+ h/p for several years on a stock block while others split in half at just over 400. I wouldn't waste my money on aftermarket internals unless it's a purposful piston c/r change or long rod/stroker kit. Once the block lets go (and it will) those costly internals have an excellent chance of being destroyed. Also...don't kid yourself into believing the likes of DSS and others who claim their stock block meraciously holds insane h/p levels safetly. There are many examples of them failing at levels surpased by factory stock blocks.

    There is some good reading here... http://www.turbomustangs.com/techarticles/stockblock.php

    You can also do some reading over in the forums...as there are a good number of us that have eclipsed the 500 mark and lived to tell the tale.
  18. Speeds8erM-1

    Speeds8erM-1 Founding Member

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    Look at Barry D's old stock blocks on TurboMustangs.com, his car was making 620 rwhp with a hyperutectic shortblock and it would split the block and not even hurt a piston, that shows the tune was close if not right on but yet the block splits.

    I have talked to guys at the track and known people that had good luck with the stock block in track cars, it's the street cars that get beat on regulary that eat the block. My friend had a 347, balanced, girdle, tuned, methanol, everything, Vortech T Trim at 12-13 psi and it split the block, he didnt even know it was split until he took it apart to put the rotating assembley in a Dart block. Car last a couple months with the stock block. He did rev it pretty high though.
  19. Rick 91GT

    Rick 91GT SN Certified Technician Site Sponsor

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    I agree there are way to many variables when discussing stock blocks. RPM kills motors and is especially hard on a stock block even at a internal balance and excellent machine work. We have broken stock blocks at 350RWHP in NA form and have had them last in the 600HP range with a power adder. Why some last is a good question, most is in the tune or the way/where the motor makes power.

    I tell my customers that if they are planning on big power, plan to buy a aftermarket block. If they can afford it do it the first time, if not atleast add a main girdle to keep the internals where they belong when it splits, then transfer then to the aftermarket block.

    It's not just the 302 blocks, the late model 351 blocks have the same issues.

    The cost it takes to build 2 stock block set-up pays for an aftermarket block set-up.... Just my $.02
  20. dubbsix

    dubbsix Member

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    Well you cant include the cost of internals when we are comparing just blocks. Of course by the time you tally everything up its going to be more expensive than buying an aftermarket block.

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