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  #1  
Old 05-05-2004, 03:39 PM
Plymouth10 Plymouth10 is offline
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Default 360 into a 340 well sure!

Advertising is not allowed - now has spacer conversion kits to allow a 2.5" main 340 ,318,273 crank to be used in 360 blocks, convert your 360+ .040 to a 340. this has been in the works a while, great thing for us 340 guys.
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  #2  
Old 05-11-2004, 04:02 PM
1980cobra 1980cobra is offline
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I SEE THAT AS A WASTE OF TIME!!!!! WHY???
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  #3  
Old 05-11-2004, 04:21 PM
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check the price of 340 used blocks, only 180,000 or so made not a lot left laying around, some sure, 360 blocks give aways almost, good for that reason.
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  #4  
Old 05-11-2004, 05:51 PM
1980cobra 1980cobra is offline
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just use the 360 block and leave the 360 crank in and save some $$$$ who will know its a 340 or 360? why would you want a 340 crank in a 360 block?is it power or just saying you have a 340?? a 360 will make more power then a 340 any way
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Old 05-11-2004, 07:31 PM
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360 make more power than a 340 depends and what modifactions you are referring to, many people prefer the short stroke large bore combo including myself, and prefer the 2. 5" main 340,318,273 cranks over the 2.81" 360 crank which can weigh up to 9lbs more than a forged 340 crank. most racers prefer less Mass on rotating weight/recrip weight , and smaller mains. most 360 cranks are in the 59 lbs range. Oh and we much prefer the internal balance of premay 72 cranks, even though you can do the same with a 360 crank. We ran a "small main "3.58 360 crank in a R-3 engine that did well. there is lot of demand still for 340s out there, hence the new Mp resto block,and this spacer kit. and if 360s make more power, why were all the pre R-5 race engines based on the small main type crank , used in Nascar, trucks and first year of w.c.
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  #6  
Old 05-11-2004, 07:45 PM
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we race 360s to, but we much prefer 340 based engines, with either 3.31 or a 3.46 crank, {340 - 358}
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  #7  
Old 05-11-2004, 09:06 PM
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1980cobra;

Also, 340 blocks of the stock OE fashion are hard to come by with owners thinking there gold. Priced accordingly to what they think.
Race blocks are expensive as well. Though a way better deal, the biggest problem can arise when class racing.
Your Fords and them there Chevy's do not have a 360 cid engine. Many times I see cid limits at 350-355 cid. Destroking the 360 is easier this way due to the wide verity of stroker cranks for there main size. (Smaller than a 360)

Heres an interesting old dog trick you may not have heard off,
360 crank cut down to 340 main size into a 340 punch out some to make 372 cubes.
Hummmm, sounds like a new thread topic to start.
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Old 05-11-2004, 10:27 PM
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Yea we have done that to even a 360 crank in a 318 {344} ci that does work and shed the weight, still have the ex ternal balance issue to deal with, or leave it.. i am gald to see this spacer kit, i thought of the idea many years ago, but many other's were on it already. there is a similar Chevy kit i think for 400ci not sure, Trend in cranks at least busch,nextel cup etc, is even smaller mains, getting close to 2". even though rotating weight is not as important as recriprocating weight it still is a factor , good point rumble on the after market 340 blocks and the R class blocks price is WAY up there, resto block is 1500, and a nice piece.
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Old 05-11-2004, 10:53 PM
72Challenger 72Challenger is offline
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Actually the big advantage to the smaller mains of the 340 journals is not the lighter weight, but the smaller circumference, and therfore less friction. The 360 main is 12.4% larger, that's 12.4% more friction when spinning it.

Out on the rod journals you get a double benefit, less weight and less friction. Honda bearing sizes are getting popular in engines that don't have to last very long.
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Old 05-12-2004, 08:09 AM
1980cobra 1980cobra is offline
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i guess i am lucky. i only have 2.25 mains
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Old 05-12-2004, 08:52 AM
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that is kinda what i meant, less mass, less weight, less to spin.
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  #12  
Old 05-12-2004, 09:27 AM
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As a long time Mopar racer, I'm delighted the main spacers are now readily available. One of the main problems the average Mopar racer faces is getting parts together that will fit!

There are lots of serious billet cranks(used) out on the market now, but they are all 2.500" main size. The average guy buys a used billet crank for $700-1200 but then must buy a race block to put it in. These spacers will allow a more readily available 360 block be used. And, for a lot of applications, the 360 block will live.

This little item just makes it easier to race Mopars.
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  #13  
Old 05-12-2004, 05:49 PM
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340 - 360 with stock strokes produce a very similar torque!!
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  #14  
Old 05-12-2004, 05:54 PM
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i know of TWO people that took everything out of a 340 and install in the 360 than picked up 2 tenths,Drag racing 1/4 mile.nothing talking piston and crank
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  #15  
Old 05-12-2004, 06:05 PM
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Once again is all the in parts, and modifactions, hard to compare the 2 without knowing that, perhaps the 340 did not have a much money or time put in it.. apples--to apples MM did a good 340 dragon slayer build up a while back..
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  #16  
Old 05-12-2004, 06:05 PM
72Challenger 72Challenger is offline
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The fact is, the amount of power produced by an engine is directly proportional to the amount of heat produced (amount of fuel burned) and by how efficiently that heat is converted into mechanical motion (compression ratio, combustion chamber shape, etc.) Period.

A 360 and a 340 with exactly the same induction systems and exactly the same compression ratios and exactly the same heads will produce exactly the same peak power. The 360 will do it at a lower RPM is all, because it will generate more torque at a given RPM. That is an advantage in a drag race if you are swapping a 360 in for a 340 without making any other changes, since you will pull through the gears more strongly. BUT, you will top out faster, and loose torque at a lower RPM, so if the guy using a 340 uses steeper gears to compensate, they will run the exact same time. OR, if the gears were such that the 340 was topping out exactly at the end of the quarter to begin with, the 360 will crap out before the stripe, and actually be slower!

So to say that one engine is PROVEN quicker than another can only be true if you limit the conditions to those favorable to your position. Someone else could just as easily PROVE the other point by changing the conditions in their favor!
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  #17  
Old 05-12-2004, 06:08 PM
ohioDemon ohioDemon is offline
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i had 2 340 cars and they were both fast cars. when i built my 360. i found it was quite quick.
i beleive a lot of it had to do with that extra stroke.
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  #18  
Old 05-12-2004, 06:10 PM
eric414 eric414 is offline
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all i know is that he took the heads and cam off of a 340 put on a 360 and pick up two tenths.no other mods.why did mopar stop making the 340.oh the 360 made more hp and tq with the 340 heads and cam than 340 did.
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  #19  
Old 05-12-2004, 06:13 PM
eric414 eric414 is offline
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thank you ohio demon
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  #20  
Old 05-12-2004, 06:21 PM
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Emissions was the main reason of the 340 going away,was a high performance engine from 68up , never really went away there was the chrysler kit car era mid -later 70s, were you could buy 340s stage 1,2,3, X blocks, {glidden era} , then the R class blocks of today, and now the resto 340 block.
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  #21  
Old 05-12-2004, 06:27 PM
72Challenger 72Challenger is offline
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I already admitted that the 360 will have more torque. But it will NOT have more horsepower. It will just make the same HP at a lower RPM. This is an advantage on the street with gears meant for good gas mileage, which is why Mopar quit making the 340.

The fact that a couple guys swapped induction systems with no other changes and went quicker doesn't prove the 360 is more powerful, it proves that their cars weren't geared properly for maximum 1/4 mile acceleration with the 340. Nothing more. It is just as likely that with different gears and a different vehicle weight, that someone else making that exact same swap will find that they loose 2 tenths.

It's all in the combination.
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  #22  
Old 05-12-2004, 06:30 PM
Plymouth10 Plymouth10 is offline
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Agree, there..
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  #23  
Old 05-12-2004, 06:32 PM
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quit for the street, but there were crate 340s for many years after 73...
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  #24  
Old 05-12-2004, 06:36 PM
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good "rumor "mill is there might be a 340 MP crate soon out,using the restoration block for many spec engine oval track divisions, like the new ASA late models, spec trucks etc, will see..As there is a new demand for this type of spec engine.
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  #25  
Old 05-12-2004, 08:43 PM
ohioDemon ohioDemon is offline
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the only other thing i can add to this is when i build my next motor.
i will be using a 340 block that i have. i will bore it .030 and it will have a 3.79 crank in it.
there really is no replacement for displacement !
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  #26  
Old 05-12-2004, 09:05 PM
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there can be a replacement of cubes on a oval tracks, .. hey dont get me started on 318s! 3rd choice, 230hp with a very poor 2brl set up, just waiting for mods, limited bore is the setback.. i really like all the la sb's..that destroked 340 block with the 2.96 crank was a good trans am engine..
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  #27  
Old 05-13-2004, 06:54 PM
1980cobra 1980cobra is offline
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i like mopar too . as you know my brother was one so i am cool with mopars. most of the cars run auto's
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  #28  
Old 05-13-2004, 06:59 PM
72Challenger 72Challenger is offline
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Hey Rumble,

I was doing a little research, seems it's on the level. Here's the link to the rulebook:

http://www.nmraracing.com/rules/hot_street/

And these guys are running in the low nines. Maybe some have broken into the 8s, didn't see one at their last national event. But the winner did run a 9.012 at 149.97 mph! Pretty good for a Ford, eh?

But I haven't been able to verify that these guys are running anything less than the max allowed 440 c.i. Hmm, 440, wonder where they got THAT number from?
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  #29  
Old 05-13-2004, 08:33 PM
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72Challenger; Thanks. I have seen Mustangs run this quick live. I don't doubt there potential at all, or what 1980 was saying. I would like to know the true fact of the matter of there actual displacement. If indeed, the actual dispalcement is 302 or .030 - .060 overbored, I'd like to know. And I would like to know why someone would go to such an extent of makeing an engine of 2 HP per cube or even 3 HP per cube.
How ever, cube for cube an engine is just an engine.
Now, on to the link. Thanks for the surply.
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Old 05-13-2004, 08:57 PM
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Of all the rules, I selected these to post.

HOT STREET
Base Weights:
BASE CI BASE WEIGHT
311 2700
360 2900
400 3100
440 3200
4.6L/5.4L Modular Engines may deduct 350 lbs.

Now, if I could get my fat tub E body down to 2700LBS, that would be cool! With me in it, it'll be close to the 2900 lbs. limit.
Hummm...W-9 chapman ported drag heads, M-1 single plane, etc....uummmmm, drool drool, drool.

I like the tire limit as well. Very much like a real street car. Not to crazy on width.
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