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#1
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max hp in a smallblock??
is there really a point of buying h-beam rods and forged crank, and then build a motor with 6-700hp,when the stock block only handles 500? because "how to build big inch small block mopar" says the smallblock do so!
ain't it waste of money when u can buy cast crank and i-beam rods and stay on the safe side since they also have a advertised hp-rating of 500hp. does the book say the truth? is the safe hp-factor of the stock block only 500hp?? (have an early 360block with fresh/new 4,030 bore,and is about to buy stroker crank) |
#2
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I would rather put it this way; before reaching 500 hp you shouldn't have any block wekness related problems. There are many, that put out and work with more, but they will usually eventually break. Same thing with big blocks and their cap walk, some last a while, some last longer, but it isn't a matter of wether they will eventually break or not, but when.
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#3
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Well, IMO, I try to build the bottom end of an engine so that it can take more than I plan on putting through it in the first place. Yeah, some say its overkill, but the way I look at it is if I plan on putting 400Hp though an engine, Ill build it for 500+ so that it will hopefully last longer. Plus, If I ever decide to do more to it down the road, like throw Nitrous on it or something like that, Im already good to go.
The biggest reason though, is longevity. I will give you an example, one of my friends built a 383 stroker out of his 350 Chevy 4 bolt main block. He decided that he wouldnt be putting more than 400-450hp through it, so he bought a cast stroker crank that was advertised to handle 500hp. The engine ran great and ended up dynoing out to about 425hp. After he had it a few months, he started to really get on it with the engine, and ended up snaping the crank and sending a couple of rods through the block and oil pan. Now he has to start over from scratch because he wanted to save a few hundred buck in the first place. Ends up, its going to cost him thousands that he had into the engine plus he will have to spend thousands more to build a new one, so it didnt save him anything in the end. If you want to build a good, reliable engine, pony up for the better parts, 9 times out of 10 it will save you lots of time, money and frustration down the line. |
#4
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All I would say is that you take a 400 hp motor and turn it hard all the time and its the same thing. Not will it but when will it. And I like the Idea of reusing parts not replacing.
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#5
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yeah- if you are going to race it will break sooner or later no matter how tough you build it. I have a 2.2 that is running 25 pounds of boost and nitrous(400+WHP). Got over 200 runs on it- it's just a matter of time before the one on the stand takes it place.
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#6
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Quote:
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#7
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I have a copy of the same book. The reason for most failures associated with the small block is the oiling system limitations, a lack of sufficent oil pick-up cannot be over come by any modifications down stream from the oil pump outlet. A myriad of modifications are recommended to over come the oiling problems, some work others are band aids that delays the failure. Mopar sells 340 replacement blocks that will get you to a safe 600 HP and then a step up to the R-3 blocks is next. Think of it this way a 3600 lb car with 400 HP will produce approximately 9 HP per LB this is more HP than any muscle car era car produced with few exceptions. Do you think that 1968 340 engine will take more stress now, than when it was new?
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#8
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i was told once that a older block would be stronger than a new one because it was heated up and cooled down hundreds of times ,like heat treating it or stress relieving it ,not sure how true it is because its casted and the metal is more like dirt when you cut it.
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#9
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I'm finding out that when you start really pushing alot of power through any stock block, the question isn't if it will break, just when will it break
I have seen the cast cranks hold up pretty good, but stock rods fail fairly often. This is mainly street and bracket cars. Endurance / oval track racers probbly need the stronger parts because they keep the RPMs up for alot longer time. |
#10
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Crank, that would be called a thermo cycled block or seasoned. These blocks have been stressed relieved and are best for builds in the stock block area.
A new engine in a new Dodge truck for example would be a good choice because it is new and thats it. If you decied to use it, it would need to be stress relieved. The same for any race block through MoPar or really any company would need this. From 451------ Quote:
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#11
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I agree with 73 and crank. Build it stronger than it has to be and it will last you a lot longer. Also, if you are going for truly insane power levels, step up to a better block. I would not run mush over 500 thru one. I get good results and long life at up to about 450. I haven't ventured beyond that with a stock block yet. :-)PCRMike
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#12
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Quote:
It's the same principle that have folks putting light weight fly wheels on so the engine will rev quicker at the expense of a smoother deliver of power with the heavier flywheel. Or putting light weight wheels on so the suspension can react quicker so the tire stays in contact with the road better vs a heavier wheels that skips over bumps in the road.. |
#13
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Ive been squeezing 550+ hp from my cast crank, stock rod, 360 for about 5-6 years now. No problems yet
but I know its inevitable if I dont change my combo. Stroker kit w/ H-beam rods and 4 bolt mains are in the future; although, I might just save up for the R block and go ape with the power
can you say 9 second small b
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#14
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Hughes says that 600+ is sustainable in a SB Mope, with a girdle. My brother ran an 800+ HP 340 based SB for years. :-)PCRMike
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#15
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I have a Hughes girdle, he said it was better than machining for a four bolt cap. I agree.
I have purchased alot of stuff to get my 408" together but lack the heads and cam. I am more than likely going to do Indy heads. I haven't had time to get it going because they keep sending me to war, dammit. I think I will be making a little more than the said threshold. I am using a D1-SC blower(around say 10 psi?), water/methonal injection, forged 4.00" crank, forged diamond quench dome 8.5:1, hyd. roller lifters, roller rockers, the said closed chamber Indy's, a blowthrough 750 Holley on top of a Indy or Eddy Super Victor single plane. The cam choice isn't made yet but has to be 114deg LSA. The 1971 era 360 will be bored .030" over. Can anyone give me an educated guess on where my HP is going to come in at? I have no idea but would love it to be over 600hp. Maybe I should start another thread. Don't mean to thread jack. |
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