340 hp capabilities?

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Its all rolling the dice. The block that is cast less than optimum, has porosity or shift, vs. the one that came darn near perfect. depends on the particular block. Great for your dad however!
 
You need an aftermarket block.

Seriuosly, some people must think that those of us who invest in a good block are stupid. Chrysler didnt make the X blocks because people were standing in line to buy them. They NEEDED them. To spend ONE red cent trying to make that kind of HP is idiotic.

And ditch the engine builder who told you hard block creates a thermal whatever by anyhow because he is goofier than a bowl of fruit loops. Herd block has a purpose. If used correctly it has benefits.
 
07raptorgytr said:
Looking to build a beefy 436" out of a 340 block. Was just curious what hp or around what ball park hp do these blocks split apart? I have a 71 factory production block. Would love to get a R3 block instead but I'll take what I can get.
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I would look into a race block myself. There just hard to find now from what I am reading.
 
It sounds like you really want to push the limit of a stock block . If you want to be safe, build it to 550 hp with quality parts . Anything above that places it in the realm of uncertainty.
 
07raptorgytr said:
And that's the thing. It isnt like I will be out there power shifting from light to light at or above 6000 rpm. It will occasionally go to the strip on a Friday night for fun.
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You are going to drag race it but you are going to shift it like Grandma when you do...really?
 
barnett468 said:
You are going to drag race it but you are going to shift it like Grandma when you do...really?
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What I ment by that statement was the fact that 95% of the time this motor won't be thrashed on, but I want the power to be available if need be. As for the drag racing part, it was just a simple statement that I may run a few passes on a Friday night.
I just wanted to make it clear this isn't a motor for a all out drag car, so the stresses would be a bit different then street driving.
 
Build it with twice the abilty to handle the intended HP.
 
07raptorgytr said:
What I ment by that statement was the fact that 95% of the time this motor won't be thrashed on, but I want the power to be available if need be. As for the drag racing part, it was just a simple statement that I may run a few passes on a Friday night.
I just wanted to make it clear this isn't a motor for a all out drag car, so the stresses would be a bit different then street driving.
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Yes, but the point remains that you are still going to shift it fast under full power at some point, so you could just as well ask, "Exactly how many power shifts can I do with a 600 hp stroked 340?".

The answer to that is somewhere between none and a zillion.
 
I've got 2500 miles on my 605hp 416 (340). I bag the crap out of it. Its a street car, no fill in the block. Machinist told me its the best 340 he's ever seen for minimal coreshift and thickness of cylinder walls. Its a '73 block. I am running billet main caps and stud girdle. I think up to 600hp isn't going to be a problem. Stay away from spraying it unless you want to really roll the dice. When I get closer to a rebuild or decide to try something different I think I will throw a 150 shot on it for ***** & giggles :) Of course there is going to be some risk when going with big power, but its minimal if built right in my opinion, I don't see a bunch of threads popping up about 600hp small blocks blowing up.
 
justinp61 said:
What has it ran in the 1/8?
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I've only taken it down the track twice, running the 28x13.5s and the 3.55s out back (**** combo). I have a set of 4.30s, but need another 489 case etc. Anyway with horrible launch and best 60' of 1.74 the best 1/8 was 7.307 @ 98.4mph. The best 1/4 was 11.31 and best 1/4 mph was 128.9. Also my converter is for the street, 3200 stall. So with gears, converter and trans brake, I'd say it would be well into the 10s. But, doubtful I will ever see it, no real aspirations to run it again any time soon. Its a show car/cruiser.
 
Rodzilla said:
I've got 2500 miles on my 605hp 416 (340). I bag the crap out of it. Its a street car, no fill in the block. Machinist told me its the best 340 he's ever seen for minimal coreshift and thickness of cylinder walls. Its a '73 block. I am running billet main caps and stud girdle. I think up to 600hp isn't going to be a problem. Stay away from spraying it unless you want to really roll the dice. When I get closer to a rebuild or decide to try something different I think I will throw a 150 shot on it for ***** & giggles :) Of course there is going to be some risk when going with big power, but its minimal if built right in my opinion, I don't see a bunch of threads popping up about 600hp small blocks blowing up.
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Exactly. Last year I put 800 miles on the car, thus year Iam at 300 and the year us coming to an end for drivable weather. So with that said it isn't like there is gonna be a ton of road miles put on this thing. It is a Saturday afternoon cruiser that likes to party from time to time. The block I have is a 71 340 that Iam still awaiting on sonic numbers to come back, I also have a 76 360 block that potentially could be used as well.
 
Not as much an expert as many on here, and not to be one of "those guys", but I personally would use the 360. Lots of 360 blocks to play with, and fewer and fewer 340's, only reason.
 
I would back the stroke down, use hardblock, 2 stud steel main caps, light pistons, and not worry
 
barnett468 said:
It sounds like you really want to push the limit of a stock block . If you want to be safe, build it to 550 hp with quality parts.
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I like this train of thought. It really can be a simple build with moderate cam timing. Build the displacement big, add an excellent intake and well ported head with at least a 1-3/4 exhaust header tube if not stepped up afterwards from 1-3/4 - 1-7/8.

A small roller of about 236/240 intake @.05o is enough duration to get you there. Use as much lift as possible. Quality parts to be used only and well looked at and massaged to be used. Just don't bolt them on and run. There's good power hidden in the parts.
 
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