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  #1  
Old 04-26-2000, 02:31 AM
crackhanger crackhanger is offline
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when building a 400 stroker with a 440 crank, do i use the rods from the 400 or the 440? also, does the crank have to be rebalanced (don't see why it would), and does the cylinder bore bottoms have to be notched?

doug
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  #2  
Old 04-26-2000, 02:45 AM
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Brian_wo Brian_wo is offline
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use the 440 rods and of course the crank needs balanced,you will have to take weight off of it to get it to balance when it's all said and done.
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Old 04-26-2000, 03:02 AM
crackhanger crackhanger is offline
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why does it have to be rebalanced? the metal only has to be cut on the main journals, right? if so, that should not change the balance at all. guys, more inputs, am i right or wrong?

doug
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  #4  
Old 04-26-2000, 03:09 AM
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because by the time your done with putting the lighter smaller pistons in there the rotating weight will be much less,that means the crank will now be to heavy.
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Old 04-26-2000, 03:24 AM
MopART MopART is offline
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Brain,

You seem to be a guy who gets around. BTW, that was a cool pic. of your motor on the stand with the CPPA headers.

Anyway.... what's best, turning the crank or boring the mains? Why? I've always heard not to grind the main journals, but to open the main bores. Additionally, to convert to 4 bolt caps. This I guess is to handle all the power associated with the stroker.
With that said.... makes you wonder why guys are builing these low hp strokers and skipping some of the proceedures.... just to have one I guess..
What's your take on all this?

crackhanger,
You thinking of building a stroker? 'Cause there's a load more to it than the questions you've asked so far. You can go to the "search" option at the right corner of the board and review this info in the archive.

ART
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  #6  
Old 04-26-2000, 03:39 AM
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Brian_wo Brian_wo is offline
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Brain? lol

which way is better? good question but I look at it this way,that crank is tough even cutting .125 off of the mains and I would rather have more strength in the main cap area myself and as far as low hp strokers just to have one I don't see it that way,I see it as spending a few extra dollars to get a lighter rotating weight with a smaller lighter stronger block,I have just finished up a short block 450 cube motor thats 9.5:1 for my ramcharger,personally I have had many 440's and now have this 431 and after seeing how fast it revs and having more room in my engine bay I will never build another 440,as far as that goes I sold off all my 440's last year.

that picture of my motor is with hooker comp headers(not super comps) and I'll tell ya that they are the best set of headers I have ever had,kinda heavy but I can pull the starter just by removing the steering column and not taking even one header bolt loose,I kinda fell in to them from a local guy who bought them at a swap meet for $30 then decided to use stock manifolds and just wanted his money back.
<img src=http://www.geocities.com/wo23dodge/81.JPG>
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  #7  
Old 04-26-2000, 07:22 AM
DartGT66 DartGT66 is offline
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Check Todd's web pages like recommended in the earlier posts. There is pretty much basic information about the subject. 451's have been done both with the 400 and the 440 rods. With the 440 rod the pistons end up lighter and the rod angles are better, I would use them. Most of the engine builders turn down the cranks main journals and the counterweights to clear the block. I think the measurements of the counterweights can be found in Todd's pages. I chose to turn the mains down and not nitride or reheat the crank. It has worked just fine for four years of severe abuse, and is in like new condition. I didn't turn down the counterweights, but instead clearnced the block for them. This is because I could do the clearancing myself and this way I saved some money. However, after balancing the counterweights look like swiss cheese and turning them down could be wiser for better oil control etc. I used Eagle 440 rods; stock 440 LY rods with resized big ends and ARP bolts can handle over 7000 rpm easy with light weight pistons and balanced they are lighter than most of the aftermarket rods. I used ROSS pistons, they are about 500$ in muscle motors. KB hypereutectics are about the same weight and less expensive. Converting to a four bolt short block is usually not necessary. The stock bolts can hold the main saddles pretty well and thew first step upwards is to use ARP studs there. They have a lot bigger torque down figure, so you propably have to align hone the block with the studs. With the studs, the block is good for 600+ hp which should translate into a 10 sec B-body. If you aim higher, start considering the main cap mods.
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  #8  
Old 04-26-2000, 03:27 PM
crackhanger crackhanger is offline
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Todds web pages? please clue me in some.

doug

thanks guys
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  #9  
Old 04-26-2000, 04:10 PM
RLW RLW is offline
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http://www.phoenix.net/~atc347/451/
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  #10  
Old 04-26-2000, 06:51 PM
MopART MopART is offline
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Brian,

Maybe you can easily clear this up... From what I understand the '72 and some '73 400's are the only years that will accomodate this stroking combo.

What's the skinny on this issue?? 400's are all over the place, but how many can the regular "joe" find that were made these two years? It would be a pisser to buy one hoping that it'll work only to find that it won't after you have it tested.

ART

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  #11  
Old 04-26-2000, 10:09 PM
Old hippie Old hippie is offline
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Gents;
When building a 400/451 there are lots of false leads out there.
1) You can use virtually any 400 block for this combination (or 383 for the 431 deal). The main thing you have to look for is this: Always have any thin wall cast block sonic checked for core shift, and ANY block sonic checked if going beyond 30 thou. overbore. Some of the thin wall cast blocks will go as much as 60+ over while some others will barely go 30 over.
2) It is not adviseable to bore the main saddles out to the 440 size. Ray Barton will argue this. Most Mopar engine builders will tell you that this weakens the main webs. Believe them.
3) It is best to turn the counter weights for clearance/weight reduction in the "B" crankcase. There still may need to be some minor clearancing done at the Oil Pump Pickup Boss and at the pan rails.
4) It is NOT adviseable to modify the stock blocks for the cross bolted main caps. The stock blocks were never cast with this modification in mind. All Mopar blocks that have been cast for X-bolted mains have extra meat cast into the blocks to support the side bolts. Use a good aftermarket billet main cap and good main studs or the factory MP ductile Iron main caps with the studs unless you are going to get totally crazy with N2O (ie...high HP or multi stage stuff). Then you need to step up to a much stronger block.
5) The reason for the rebalance is fairly obvious. The total weight of the reciprocating assembly will be radically differant with the lighter pistons used in this combination. The weights for a stock assembly are not real close in terms of bob weight. The machineist that I use told me that he has checked several stock con rods and found them to be as much as 23 grams out from the big end of the rod to the small end. So, always rebalance even in a stone stock rebuild. It is very cheap insurance that your pride and joy will not shake its self apart.
Happy motoring, hope this has cleared up some of the questions about this build.
Brian....bitchin' engine!!

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The Old Hippie Hisself
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  #12  
Old 04-26-2000, 10:57 PM
MopART MopART is offline
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Thanks for the lesson, Old Hippie...
I just want to know what the guys who have them *really* do.... not that I am going to build one or anything. What gets me is all the lip ya' hear from guys that'll just talk it to death and never do anything..(not refering to anyone on the board).
I got into this with the guy who bought my Scamp (440 727). Anyway, he's never wrong... it's his way or the wrong way - you know what I'm talking about.

ART
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  #13  
Old 04-26-2000, 11:22 PM
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Brian_wo Brian_wo is offline
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all I can say is that I love mine,I don't have any numbers I am proud of because it has only been to the track one time and I could not get any traction,out of three runs it ran a 12.59 spinning in 1st and 2nd but I sure can feel the diff in the way it revs compared to all the 440's I have had.
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  #14  
Old 04-27-2000, 05:29 AM
451boy 451boy is offline
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On the subject of 400 blocks. Any year of 400 block will work just fine for a stroker motor. KB sells the pistons in as little as 0.020 over so if your block will clean up at 0.020 over, and you can use the KB piston then go that route.

The only 400 block which has any extra value is the early 1971 casting. These blocks have a solid main web casting which should be capable of really handling a lot of power. Your average 451 motor doesn't require one of these '71 cast blocks but if you find one, latch onto it! I found one in a boneyard last summer. Took the afternoon off of work and pulled that sucker before anyone else could grab it!
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  #15  
Old 04-27-2000, 08:23 AM
DartGT66 DartGT66 is offline
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I have been involved with four different 451's. Three of them were short rod versions and one was a long rod. All are pump gas street engines in street cars. All the short rod engines have been built with cast cranks, and cast 400 pistons with milled tops and clearanced skirts.
They run as follows
a '71 road runner with a six pack, pocket ported 452 heads, mp 280 cam hp exhaust manifolds, 3.55 gears,weight over 3700 lbs, 14.2/98 mph.
A '83 Plymouth Voyager van, stock everything but the crank, weighs a lot, 14.51/92 mph.
A '65 Coronet, ported '452' heads with 2.14"/1.81 valves, MP 284 /.484 cam, Torker 2 intake, 900+ Holley, 2" headers, 3000 stall, 4.10 gears, weight 3100 lbs, 11.37/120mph.
A '73 4 D Valiant, Eagle rods, Ross pistons, Stage VI heads, .555" street roller cam, M1 intake, 3310 Holley, 2" headers, 3800 stall, 3.91 gears, weight 3530 lbs, 11.19/123 mph.

So you can see that it's not a 'magical' combo that makes everything run, but it is a good starting point.
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