400 with 440 pistons

[Thackdaddy]

I am doing a low cost father son 400 build (strokers are out) and I am looking for a piston recommendation. The block is a standard bore 400, a 383 forged crank, 452 heads and 440 Source factory style connection rods. The car (72 Satellite) is a street car, 3.55 gears and a 727 with 2400-2600 stall. I am looking for 10:1 compression. It has been suggested to me that I use a 440 low compression piston. Has anyone done this? Good or bad idea? Thoughts or any recommendations or things to watch out for?

 

[w.Hudson]

My best friend did something similar.

He used a 72 440 low compression standard bore size piston in a 383. It had near zero deck height. The engine size came out to 396 cubic inches.

It made for a real nice combination. It was balanced and used 906 heads. He ran the stock cam from a 375 hp 440.
Stock 335 hp 383 intake and carb.

It was impressive.

 

[33 IMP]

Looks like you need a piston with around a 1.93 compression height piston. If you can find a 440 piston with that ch, it should work. BUT, If its a flat top, you will have to be wary of too much compression ratio, and valve to piston clearance. The very lo-po 440 piston won't have any valve notches. And remember,,the 400 bore is already .020 bigger than the 440, so a .040 440 piston will be .020 over in your 400.
Edit. Looks like summit has several versions of cast piston with 1.912 ch. 424 NC is one. If you search 440 Chrysler pistons on summit site, specify the ch you want and they will come up.

 

[BSB67]

I think there are, or used to be 1.91" 440 pistons available

 

[SlinktRR]

Might have to check out swap meets and bring a caliper you might get lucky. The 440 I got as a spare engine for my car had been built as a homebrewed stroker using an eagle 4.15" crank with Mopar performance 9.0 CR replacement 400 pistons from 80s era direct connection and stock LY rods. He had 906 heads with this setup. I sold these parts and used the block and crankshaft for a new stroker with icon custom pistons. It's possible to get a good deal for used pistons that will work for your application but will take some time. Check with a place like Stephens performance to get used factory parts or wait for Carlisle next year.

 

[qkcuda]

I built my first 400 using MP cast 9:1 440 pistons, stock 400 rods and a forged crank. It was near zero deck. The engine ran well and dyno'd at 415 hp and 450 tq. The two issues were they were heavy and required external balancing, and as has been said, being flat tops you have to watch piston to valve clearance. I built this about 20 years ago. Today I would just buy KB Pistons.

 

[33 IMP]

Qkcuda is right on it! Looks like KB 400 hypers are cheaper than the 440 cast. At least, at summit they are.
You might find the 440s cheap somewhere....... but I'm with quick, kb is a better option.
Me, I'd build a cheap stroker with icons from 440 source.

 

[BSB67]

Buying the right piston for the application. Crazy.

 

[66Satellite47]

Dah, a stock bore 440 piston will not work in a stock bore 400 no matter what the compression height is. What length con rods are those? A flat top is no big deal, fly cutting the valve notches is a normal practice to match the cam being used.

 

[33 IMP]

Dah, a stock bore 440 piston will not work in a stock bore 400 no matter what the compression height is. What length con rods are those? A flat top is no big deal, fly cutting the valve notches is a normal practice to match the cam being used.

True, but a .030, .040, or .060 will.... if the c.h. is right.

 

[YY1]

Following the math above, wouldn't a .030 over 440 slug be .010 over in a 400 bore?

That might be easier on the machine shop.

Aren't 400 pistons notoriously short to begin with?

This is one of those doable projects that no one ever seems to talk about.

Great info.

Thanks to all.

 

[qkcuda]

I used .060 over 440 pistons which made it a .040 overbore in the 400. The main reason I did it back then is that there were no off the shelf 400 pistons available with a higher compression height. Since then, KB solved that problem.

 

[Thackdaddy]

I am currently thinking about the Silvolite 1276-030 Cast pistons, they are $223.99 at Summit and as mentioned above that would be .010 over. They have a CH of 1.912 in so if I did my math right they would be .020 down. About the KB pistons, my plan at first was this https://www.motortrend.com/how-to/mopp-0009-how-to-build-a-blueprint-bottom-end/ However, I have to trust my machine shop and when I said Keith Black Piston you could have heard a pin drop in the place. The connecting rod I am using is a 440 source factory style rod in stock length of 6.358".

 

[33 IMP]

I threw some numbers in the calculator, and came up with 8.5 to 1 cr. Should be good with a mild cam that doesn't need valve reliefs.

 

[RemCharger]

Make sure the skirts don't hit the crank.

 

[qkcuda]

Check out this cam currently for sale on this site. Very similar to the one I used in my 400. Great street manners and power. Don't believe the powerband, it pulled past 5000.

 

[66Satellite47]

My OEM 383 2bbl cam would go to about 5000 RPM before it gave out. As I became a drag racer I was looking for 7000+. I should have been satisfied with 6500 to save my cranks.
Good luck on your build.

 

[RemCharger]

Amen to the stock cranks blowing out.
But do love the high hp rpm.

 

[Hemirunner]

I probably have some used TRW .030 forged slugs

 

[66Satellite47]

Amen to the stock cranks blowing out.
But do love the high hp rpm.

Ya so did I. My 440's had shot peened LY rods with good bolts. TRW style DC 11.5 pistons 7000 all the time. Lasted 300 to 400 runs. The 400/452 7000 -7400 RPM about 350 runs.
I have to believe the current aftermarket cranks are better.