400 stroker…470 or 512?

[68 HEMI GTS]

Love my 512(s) plural. Not sure about that slow reving part… only motor I would consider with that 3.54 gear.



https://youtube.com/shorts/g5wsvGqd4xA?feature=share

 

[68 HEMI GTS]

For longevity, I would use a 4.150 stroke. 500 inches in a 400 block will scream! Just my opinion of course. ruffcut

the majority of 4.15 kits for the 400 use a really short CD. I have one, not a huge fan of it. It does rip when it’s fresh though. Wouldn’t be my choice at all for a street motor.

 

[Xp29h]

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?

400 to 512! I figured if I’m going to spend the money and same money to be exact, I wanted the power! If you keep the compression ratio down a bit, pump gas will be fine. Cruise all day long (of course you will not drive by many gas stations without stopping) and still be able to get after it when you want to!

But at the end of the day, you’ve got to be happy with your decision either way! I wouldn’t change a thing on my 512 build. Do it again in a heartbeat!

Good luck on your decision and build. Most of all have fun doing it!

 

[Curiousyellow71]

Love my 512(s) plural. Not sure about that slow reving part… only motor I would consider with that 3.54 gear.


https://youtube.com/shorts/g5wsvGqd4xA?feature=share

Simply Awesome video...

 

[Geoff 2]

512, no brainer.

 

[IQ52]

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.

Early on I found out how quick a small block Chevy revs.........

Before I had my own dyno I took a 451/400 we built to another dyno. After the warm up the dyno operator cracked the throttle a coupla times and said, "She revs like a small block Chevy!"..........Ah Ha.

Months later our 500ci/440 was on the dyno and the operator exclaimed, "This one revs like a small block Chevy too!" Tah-Dah!

So I KNOW how a small block Chevy revs.........even though we didn't build one 'til years later and run it on our own dyno.........I had testimony from an experienced dyno operator/NHRA Stock Eliminator racer.

 

[TexasRoadRunner68]

400 to 512! I figured if I’m going to spend the money and same money to be exact, I wanted the power! If you keep the compression ratio down a bit, pump gas will be fine. Cruise all day long (of course you will not drive by many gas stations without stopping) and still be able to get after it when you want to!

But at the end of the day, you’ve got to be happy with your decision either way! I wouldn’t change a thing on my 512 build. Do it again in a heartbeat!

Good luck on your decision and build. Most of all have fun doing it!

Was the rotating assembly drop in or was there did you need to clearance your block?

What CR were you using for street? I was hoping for 10.5:1 with a 78 ish cc chamber based on what I have been reading.

 

[TexasRoadRunner68]

Just do a 440

I have an original 70 HP2 block and crank, and will probably be picking up a 75 4006330 block I found locally for cheap. I like the idea of a stock looking motor, however it seems the 400 is just more durable if you want to run it hard.

I could just throw together a quick 440 with reconditioned rods and new higher compression pistons and all ARP hardware, but then you may as well almost replace the rods…and there’s the cost of rebalancing etc.

 

[furious70]

Low deck can give more header clearance too

 

[Xp29h]

Was the rotating assembly drop in or was there did you need to clearance your block?

What CR were you using for street? I was hoping for 10.5:1 with a 78 ish cc chamber based on what I have been reading.

It was pretty close to drop in.. we did a little work but not a ton. We believed that all tolerances needed to be checked and gone over regardless!

The CR is 9.7:1. I kept the CR down but brought the pistons to darn near deck height so lots of Quench or what my buddy calls squish! Lol! He claimed at the time that was where the power is! I believe him! Goes great at that CR and zero issues! It likes pump gas at 93 octane with a little octane boost.

I’m in hopes to fire it up this weekend and get it out on the road weather permitting! It’s Maine!

My kit came from 440Source and zero issues with those guys and parts. 100% spot on and great to deal with! I went with the .572 cam and the CNC stealth heads! Had to upgrade valves, springs and locks but easy to do just more money! Lol! Speaking of which, Harland sharps on top too. If you want more info, I will be glad to dig out the build book I kept and get you the rest of the info. Just let me know!

 

[451Mopar]

Usually the oil pickup boss needs a little clearance. I have not needed to clearance anything else, but do check the bottom of the bores for clearance.

 

[68 HEMI GTS]

Usually the oil pickup boss needs a little clearance. I have not needed to clearance anything else, but do check the bottom of the bores for clearance.

same, I’ve built enough 400/512’s now I already know where to grind the boss. I don’t even mock them up anymore. Cylinders on those always have miles of room.

 

[TexasRoadRunner68]

same, I’ve built enough 400/512’s now I already know where to grind the boss. I don’t even mock them up anymore. Cylinders on those always have miles of room.

Any thoughts on the standard 512 crank vs the ultralight crank? They say it revs faster, but I hear some people say the weight reduction can be so close to the centerline that it practically makes no difference in a street car.

 

[68 HEMI GTS]

Any thoughts on the standard 512 crank vs the ultralight crank? They say it revs faster, but I hear some people say the weight reduction can be so close to the centerline that it practically makes no difference in a street car.

I’ve built a few of each. Anytime your pushing a stock block less rotating mass is better. Will you feel the difference, nope probably not. But for the little bit of cost difference…