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400 stroker…470 or 512?

TexasRoadRunner68

TexasRoadRunner68

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Sorry for duplicate posting. I have been researching and pricing out a build for my 70 4 speed Charger RT. After going back and forth, it seems that after adding the cost of reconditioning rods, new pistons, balancing, etc…its almost more cost effective to buy a stroker kit for what you get in the long run.

For those of you that know these, would I be better off with a 470 or 512? It’d be a street and occasional track car with a hemi a833 and 3.54 Dana 60. Goal would be trick flow 240s and 10.5-11:1 compression with a decent street hydraulic roller cam. Hopefully something nice and lumpy. I might have to settle with 440 source stealth heads for a while until I can swing an upgrade.

I know the 512 puts out more torque but supposedly revs a bit slower due to the bigger stroke. The 512 also might need the block to be clearanced.

Is the trade off worth it? I’m all for a 470 it revs fast and puts out basically the same power as a 512. I can also assemble it easier. However if they both rev about the same and the 512 is just more power, I’d go that way. I know people seem happy with either. They cost the same (minus any block clearancing costs). How much difference is 52 cubes?
 
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I don’t know how well the short nearly slipper skirt pistons hold up, but I like the 496 setup that uses an RB length rod and the 4.15 inch crank.
 
I would suggest to avoid anything with the larger mopar rod journals. The bbc 2.2 journals and bbc rods will make clearancing minimal.

4.25" crank works great. We have been running a 440 with 4.25" crank for 28 years. Buy as many cubic inches as you can. :thumbsup:
 
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The 512 is the same as the 383/496. Just the extra 17 cubic inches. Plus allowance for overbore/honing. W the 440 Source stroker kit on the 383, no clearance issues at all. I'd assume the same for 400/512.
 
Every time I hear about a 451 or a 470 reving fast I think of a guy named Rodney back in grade school. Everybody thought Rodney had fast fists and would win any fight he got into. Until Rodney got into a fight with a bigger guy who was just as fast as Rodney.

I don't think you could tell the difference in the rev's of a 383 or a 540. I know I couldn't.

Just build what you think you want.
 
IQ52 said:
Every time I hear about a 451 or a 470 reving fast I think of a guy named Rodney back in grade school. Everybody thought Rodney had fast fists and would win any fight he got into. Until Rodney got into a fight with a bigger guy who was just as fast as Rodney.

I don't think you could tell the difference in the rev's of a 383 or a 540. I know I couldn't.

Just build what you think you want.
Click to expand...
I like this!!
 
How much would it cost to build a stock stroke 400 using the good heads etc? Throw more gear in the rear and go with GV OD unit. Been awhile since thinking of doing the same but with a lighter car. I've grown to like the short stroke engines as time went on. They rev faster and can still produce a good amount of torque. Old school of thinking is that you need a long stroke to produce torque but these days, that's not set in stone.
 
For longevity, I would use a 4.150 stroke. 500 inches in a 400 block will scream! Just my opinion of course. ruffcut
 
TexasRoadRunner68 said:
Sorry for duplicate posting. I have been researching and pricing out a build for my 70 4 speed Charger RT. After going back and forth, it seems that after adding the cost of reconditioning rods, new pistons, balancing, etc…its almost more cost effective to buy a stroker kit for what you get in the long run.

For those of you that know these, would I be better off with a 470 or 512? It’d be a street and occasional track car with a hemi a833 and 3.51 Dana 60. Goal would be trick flow 240s and 10.5-11:1 compression with a decent street hydraulic roller cam. Hopefully something nice and lumpy. I might have to settle with 440 source stealth heads for a while until I can swing an upgrade.

I know the 512 puts out more torque but supposedly revs a bit slower due to the bigger stroke. The 512 also might need the block to be clearanced.

Is the trade off worth it? I’m all for a 470 it revs fast and puts out basically the same power as a 512. I can also assemble it easier. However if they both rev about the same and the 512 is just more power, I’d go that way. I know people seem happy with either. They cost the same (minus any block clearancing costs). How much difference is 52 cubes?
Click to expand...

For street, pump gas, Hydraulic roller (around 6,000 RPM max?), I would do the 4.25" stroker with the 24cc dish pistons (around 10.5:1 Compression with 78 cc trick flow 240's?). You could build for higher compression, but for a driver I would want something that could be run on lower octane pump gas.
Not sure what octane the new proposed E15 Fuel will be?
The Bob Weight of the 512 (2140grams) is actually lighter than the 470 (2160 grams). Extra torque and lighter rotating assembly with the 512.
With the GM 2.2" crank pins and rods, block clearance should be pretty easy.
 
Myself, I like the longer pistons for a street engine. 470 will still make plenty of steam.
 
Both will make north of 600-horsepower, relatively easily with your cylinder head choice. The 470" low-deck with have additional CH and a more preferable rod-ratio (depending on how much weight you put into that). The 512" low-deck has the advantage of displacement, likely creating another 50 ft/lbs of torque and dropping the actual torque peak (RPM) down considerably.

To me, the choice is (470" w/ standard-port heads) & (512" w/ max-wedge heads). Both of these combinations are nearing the limits of the factory blocks, and both will make the power you want, just at different RPMs. There isn't anything like a stick-shift car at 6,500 - 7,000 RPM. With a manual trans, big torque & sticky tires tends to break parts fairly easily.

Another factor is, do you have the suspension and tire to manage the additional torque on the street?

Build either with the lowest static compression ratio offered. My 470" is 9.6:1 with 84cc Edelbrock RPM heads. Trick Flow IIRC is 78cc.

I get a good laugh when I see these Big Wedge or 572-HEMI cars with.. Cooper Cobras on the rear (or any of these generic types of tire). REALLY!? My 5.0 LX Coupe in HS would blow those off with only 300 ft/lbs of torque! :D So make sure the rest of the car is dialed in to handle the big torque either of these strokers will produce.

Personally, you aren't going to go wrong with either.
 
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Let’s seeeee.......
For X amount of dollars you can have 470 cubes....... and for exactly zero extra dollars you can have 512 cubes?
Yeh...... no question what the choice is there(for me at least).

As for the piston CH dilemma......
The 451, 470, 512 all have the same piston CH...... a nominal 1.32”.

The difference in stroke is accounted for with a different length rod.

The reason the bobweight is lighter on the 512 is because the rod is shorter.
 
PRHeads said:
Let’s seeeee.......
For X amount of dollars you can have 470 cubes....... and for exactly zero extra dollars you can have 512 cubes?
Yeh...... no question what the choice is there(for me at least).

As for the piston CH dilemma......
The 451, 470, 512 all have the same piston CH...... a nominal 1.32”.

The difference in stroke is accounted for with a different length rod.

The reason the bobweight is lighter on the 512 is because the rod is shorter.
Click to expand...

There are some differences if you're purchasing from 440-source. CH with their 470 kit is 1.480-1.485. 451/512 have the 1.32 CH.

Again, this is in the realm of rod-ratio in importance. To some it actually matters, to others it makes no difference to run a 1.32 CH vs. 1.48 CH. Both are better than the 500.
 
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The rod ratio of the 4.250/6.535 combo is 1.53. Same as a stock BBC 454 or a 4” crank in a SBM with a stock length rod.
In my mind, that’s not even remotely an issue.

I guess I never looked to see how 440 Source did their 470(since I’d just go right for the 512).
If you use a 6.70” rod, then you’d use the 1.32” CH piston.

I really like the 4.25 stroke in the 400 block.
 
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