400 to 451 stroker questions

RustyRatRod

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Well, according to Ken Heard at Oregon Cams, the factory Chrysler camshafts are hardened nearly to the core. It wouldn't surprise me if the cranks were too. A good (old) crank grinder could tell you real quick like about how deep the hardness is. I just bet you'd be surprised.
 

440outlawdart

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Have any of the posters in this thread ever built and beat on a stock 440 crank equipped 400 based 451 stroker? It does not appear to be the case lol. There is no harm in turning down the 440 crank. That isnt where you are going to break anything. The cylinder wall is likely to be the weak link.

The Mahle pistons have 1.5/1.5/3.0mm rings. Use a GNS or hellfire top ring and life will be good.

1/16" = .0625"
1.5mm = .0591"

Are we really think .0035 is a game changer in the ring pack durability? No, it's not.

And lastly, Andy mentuoned he removed the 451 manifedto from his site because it was obsolete with the parts available in 2022.

My juice cam 451 dyno'd at 500/500 hp/tq with big valve 906's at 9:1cr. It made 572whp through the manifolds on a 175hp n20 shot. The standard plasma moly rigs look perfect after 50 bottles. It had to come apart due to a split cylinder wall that showed up when it was idling in the driveway.

All of the above are facts that I know first hand. Aka not internet expert speculation lol
i built a 400/451 in the 90s.turned down a 440 crank,use ly rods.ross pistons.8906 heads.ran 10.30s on alky in a cuda
 

Jeremiah

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All of the Mahle (Ma-lah) pistons sold for performance mopar apps are equipped with a 1.5/1.5/3.0mm ring groove.

I have seen .043 rings....but no 1.0mm pistons or ring packs for a 4.375 or 4.380 bore. Can someone show me where they are in the catalog?

Also, as far as I know nobody made a metric "better than plasma moly" ring for a 4.375 bore ten yeaes ago. Only when Mahle came out with the GNS series stainless top ring pack did that get solved.

I have a 1/16 ring pack 451 with standard moly rings that has 50 bottles of nitrous through it. Rings look perfect under a magnifier. None of the moly coating is burned off.

With 1.320CH piston, 4.250 stroke crank and a 9.980 deck 400 block you will be right at zero deck or very close. You will likely need to have 80+ cc chambers to stay in pump gas territory with alloy heads or a .051+ head gasket. My 511 with 440 source heads is 11.5ish CR with a 12.5 cc reverse dome Diamond shelf piston. The other identical short block with ported MW Victors was around 11.2ish CR for reference.

Unfortunately Mahle doesn't have a 1.32 CH piston with a reverse dome. That is how I ended up with a 499 - 4.150 stroke, 1.120 CH flat top and a 6.760 rod. Mahle offers .990 or 1.094 pins. I went .990 becaise I was starting from scratch.

I searched high and low for a modern piston (coated, metric ring pack etc) for my 451 refresh and there just isn't much out there unless you get creative and use a BBC rod around 6.660ish from what I remember.

Keep in mind when looking for pistons that your desired compression height will be (deck height - connecting rod length - (1/2 stroke) i.e. (9.980 - 6.535 - 2.125) = 1.32
 

Hot Metal

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Have any of the posters in this thread ever built and beat on a stock 440 crank equipped 400 based 451 stroker? It does not appear to be the case lol. There is no harm in turning down the 440 crank. That isnt where you are going to break anything. The cylinder wall is likely to be the weak link.

The Mahle pistons have 1.5/1.5/3.0mm rings. Use a GNS or hellfire top ring and life will be good.

1/16" = .0625"
1.5mm = .0591"

Are we really think .0035 is a game changer in the ring pack durability? No, it's not.

And lastly, Andy mentuoned he removed the 451 manifedto from his site because it was obsolete with the parts available in 2022.

My juice cam 451 dyno'd at 500/500 hp/tq with big valve 906's at 9:1cr. It made 572whp through the manifolds on a 175hp n20 shot. The standard plasma moly rigs look perfect after 50 bottles. It had to come apart due to a split cylinder wall that showed up when it was idling in the driveway.

All of the above are facts that I know first hand. Aka not internet expert speculation lol

Back in 1991 my 440-6 stock balanced bottom end motor (5/16ths rings!, 9.5:1cr) with BV 906's made approx 520fwhp according to weight/mph and 660fwhp with a 175hp (rich jetted for then) shot of N20, single 850DP, Team G dom with spacer for 850 and the juice cam was the Comp Cams .650/.650" [email protected] sft cam....just some more Facts.
 
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cookietruck

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I searched high and low for a modern piston (coated, metric ring pack etc) for my 451 refresh and there just isn't much out there unless you get creative and use a BBC rod around 6.660ish from what I remember.

Keep in mind when looking for pistons that your desired compression height will be (deck height - connecting rod length - (1/2 stroke) i.e. (9.980 - 6.535 - 2.125) = 1.32

if you have full deck height or more, or can deal with a thicker gasket then someone could possibly use the Mahle 1.35CH piston, only downside is it has 8cc valve pockets instead of the typical 4-5cc.
9.98 deck height and a 6.76 rod shows to be .005" above deck if my calc is right.
 

Jeremiah

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if you have full deck height or more, or can deal with a thicker gasket then someone could possibly use the Mahle 1.35CH piston, only downside is it has 8cc valve pockets instead of the typical 4-5cc.
9.98 deck height and a 6.76 rod shows to be .005" above deck if my calc is right.

Doing the math, I would not want the top ring that close to top of the bore, especially for a power adder application. I'd rather use the 1.412 CH piston with a slightly shorter rod.
 

Jeremiah

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Back in 1991 my 440-6 stock balanced bottom end motor (5/16ths rings!, 9.5:1cr) with BV 906's made approx 520fwhp according to weight/mph and 660fwhp with a 175hp (rich jetted for then) shot of N20, single 850DP, Team G dom with spacer for 850 and the juice cam was the Comp Cams .650/.650" [email protected] sft cam....just some more Facts.

My 451 made very similar power on motor and spraying it. Smaller cam, more carb and a better (I assume) n20 tune up. Pretty cool to see the numbers somewhat align 30 years apart.
 

Hot Metal

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My 451 made very similar power on motor and spraying it. Smaller cam, more carb and a better (I assume) n20 tune up. Pretty cool to see the numbers somewhat align 30 years apart.

And before I put the BV 906's on which is all I changed it made around 460, totally stock 1968 440-6 motor,+cam/carb/intake/hdrs of course went from a best of 119mph to 125NA and then 133.9 with [email protected]@the line. Plan was to up CR to 12:1 min, never happened.
 

Lowcar

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Turns out it a 76-78 , 400 block
I'm not disappointed tho, I read a couple of places that Ma Mopar continued to improve the 400 from it's inception in 71 to 78.
If it's true, and quality control increased, I think I might have a good block. Sonic testing is in order. Picking up the 400 next weekend
At this point it's going to be a 512
Can't pass up a balanced stroker kit from 440 source for $2250

i like how your prices keep going down on these kits, order a couple at your price i'll take one off your hands and throw in a extra 50 bucks for your trouble
 

MOPARMAGA

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The Machinist that cut a 451 crank for me said it took much longer than he expected because how hard the counterweights were
 

Brooks James

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i like how your prices keep going down on these kits, order a couple at your price i'll take one off your hands and throw in a extra 50 bucks for your trouble
Chek for yourself, 440 source had the kit listed 2 weeks ago for that price
 

Lowcar

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these days prices are jumping up hourly. i too am looking to buy a 400 kit wish i would of pulled the trigger before the 300 price hike wait till tomorrow and 2600 will seem like a bargain
 

MOPARMAGA

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these days prices are jumping up hourly. i too am looking to buy a 400 kit wish i would of pulled the trigger before the 300 price hike wait till tomorrow and 2600 will seem like a bargain
Hurry up !
I paid $1200.00 for art Morrison 12 pt cage back in April. January 2022 catalog has them listed at $445.00
 

Lowcar

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there doesn't seem to be a rhyme or reason behind these price hikes other than good ole ugly greed, they used to justify it blaming it on covid now it seem's to be cause we can
 

fishmens67

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Those waiting for the Speedmaster sale are going to be very disappointed.
A dollar late and a day short.
Products are only going to go up.
He who hesitates will be lighter in the wallet.
 

Lowcar

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i had a gallon of blue paint saved in my ebay for about a week it was listed for 309.99 when i bought it a couple day's ago the price was 359.99
 
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