340 block or 360 block

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07raptorgytr

07raptorgytr

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I have my hands on a 69 340 block that is bored .030 over and a 76 360 block bored .030. I plan to stroke one of them to use in my 73 dart. What are the pro's vs con's of each? My gut says to use the 340 block. Is there anything the 340 block has to to have done that the 360 block doesnt?
 
Sonic check each and use the one with the thickest walls.
That's the best bet for longevity.

Otherwise, the 340 block is a better bet because of the small things.
Smaller bearing width equal less friction.
Bigger bore means more cubic inches as well as a host of other small engineering facts that all point to better HP.
 
That's what I was thinking on the sonic test. I just didn't know if there were aspects about the 340 block that makes it more desirable over the 360, even though they are pretty much the same.
 
The bore is about the only thing, I would sonic both and use the one with the thickest walls.
 
Do you have anything else as in parts for either? I ask for money reasons.
 
No I haven't bought any parts such as crank or rods etc.. once I make a final decision I'll buy the crank and go from there
 
I heard the smaller main bearing on the 340 was better for high revving since it would have a slower bearing speed. But was also told as long as you have a good oil system and oil clearances this shouldn't be an issue in either case.
 
The only advantage the 360 has is its cheaper.
Not that 340 is gonna make a huge difference over the 360 but since you already have it and unless your on a very strict budget the extra cubes and cfms cause of the 340 bigger bore is worth it.
 
If I'm buying a new crank it's not going to be 3.58". On then main journal difference you'll never see any hp difference, there are many strong 360 based strokers running around. Are both bores fresh?
 
Run what you want, there isn't going to be a measurable difference using either block on the same build. oooohhhhhhh, 6 cubes... yikes hold back the nitromethane from that difference. :)

Main bearing sizes isn't worth discussing related to power difference.
 
Not at this level it isn't but just the mention of it throws people into a fish eating fish frenzy.

OMG, you didn't go with the bigger bore and gave up 6 inches and saddled your engine with mad house drag slowing the engine down and making it work SO much harder generating tons more heat you'll melt the rods! OMG! The worlds ending! Run!

Seriously this is how people are splitting hairs on stupid issues like 6 cubes.
 
justinp61 said:
If I'm buying a new crank it's not going to be 3.58". On then main journal difference you'll never see any hp difference, there are many strong 360 based strokers running around. Are both bores fresh?
Click to expand...

No neither bores are fresh, so a next size up over bore is going to be needed. I know we are splitting hairs between the two blocks. I was just wondering if there was a strength factor between the two. Especially since the 340 is a 69 block, which was told was a high nickel block.
 
07raptorgytr said:
No neither bores are fresh, so a next size up over bore is going to be needed. I know we are splitting hairs between the two blocks. I was just wondering if there was a strength factor between the two. Especially since the 340 is a 69 block, which was told was a high nickel block.
Click to expand...

As mentioned have the bores sonic checked, also have them measured for wear. They may not need to be bored.
 
One thing a lot of people don't know is that a stock 360 has more torque off the line than a stock 340 but the 340 will outrun the 360 as it revs much higher and breathes better. A 360 can be built to out perform it though.
When it comes to money, $5,000 on a 360 will get you more than $5,000 on a 340 for the simple reason that the price of the parts for each is different just because the 340 has a powerful history.
 
leblanc said:
One thing a lot of people don't know is that a stock 360 has more torque off the line than a stock 340 but the 340 will outrun the 360 as it revs much higher and breathes better.
Click to expand...


oh ....not this again...lol

bring your 340 over...I got a few 360s that will disagree....
 
Well not looking at this as a stock motor vs stock motor. This will be a 414 or 418 build. The parts are all the same except the main bearing size. I was looking at this as, is the 340 block stronger then the 360 counterpart.
 
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