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Piston Question

General engine tech -- Drag Racing to Circle Track

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vht
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Piston Question

Post by vht » Tue Feb 04, 2020 6:46 pm

Looking for a rotating assy for a 400 SBC, not trying to make big HP but would like 500 or so HP. There is a ton of kits out there with the KB pistons, hypereutectic alum, I was thinking they used to have a lot of problems with these. I know you have to run more gap on the top rings, anyone have any experience with these?

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Re: Piston Question

Post by Mark O'Neal » Tue Feb 04, 2020 7:17 pm

Everyone does. It is a cast pistons. As long as you don't pretend it's not, you'd be fine.

But a forged part that is a much nicer piece isn't all that much more money.

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Alan Roehrich
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Re: Piston Question

Post by Alan Roehrich » Tue Feb 04, 2020 7:58 pm

vht wrote:
Tue Feb 04, 2020 6:46 pm
Looking for a rotating assy for a 400 SBC, not trying to make big HP but would like 500 or so HP. There is a ton of kits out there with the KB pistons, hypereutectic alum, I was thinking they used to have a lot of problems with these. I know you have to run more gap on the top rings, anyone have any experience with these?
If I were going to go that route, I'd use the Speed Pro pistons as opposed to the KB pistons. I like them better. I don't usually buy package rotating assemblies,I prefer to put my own together, and my suppliers make package deals for me.

1972ho
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Re: Piston Question

Post by 1972ho » Tue Feb 04, 2020 8:32 pm

A little off topic but I just had to throw this KB piston in there have you ever saw one like this weird one.
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Re: Piston Question

Post by Alan Roehrich » Tue Feb 04, 2020 9:02 pm

Also, Mark is correct. There are a lot of good quality affordable forgings available for that application and power level. With the advent of all of the high end companies having a dedicated entry level sub brand, excellent forged pistons are more affordable now.

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Re: Piston Question

Post by Walter R. Malik » Tue Feb 04, 2020 9:30 pm

Mark O'Neal wrote:
Tue Feb 04, 2020 7:17 pm
Everyone does. It is a cast pistons. As long as you don't pretend it's not, you'd be fine.

But a forged part that is a much nicer piece isn't all that much more money.
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Re: Piston Question

Post by bigfoot » Sun Feb 09, 2020 5:07 pm

Who.makes custom pistons for a ford ?

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Re: Piston Question

Post by hoodeng » Sun Feb 09, 2020 5:28 pm

1972, the large groove under the top ring is a gas brake.

I have been using KB hypereutectic pistons for many years now, If you adhere to their fitment instructions you cant go wrong. That also applies to application.

Some years back an importer here standardized on KB for their performance pistons, they also bought out reps from KB/United to do piston schools, most informative. You dont see that these days.

That importer has since folded, local availability went with them. KB make some pistons that suit odd combos that i have to cover, they are readily available from Summit.

Cheers.
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Re: Piston Question

Post by prairiehotrodder » Sun Feb 09, 2020 5:36 pm

i built a 406 a year ago with the scat kit which used a 9000 series cast crank and the icon forged pistons. It went together nice and i have not seen the customer since so i think he is happy. I melted down a KB piston a number of years ago in a 500 cadillac but i'm sure there was no ones to blame but myself. However i think even a cheap forged piston such as Icon would be more forgiving.

The only thing i would have prefered in the 400 kit was if .020 would have been available. I don't trust 400's at .030 for very long.
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Re: Piston Question

Post by Coloradoracer » Sun Feb 09, 2020 11:04 pm

bigfoot wrote:
Sun Feb 09, 2020 5:07 pm
Who.makes custom pistons for a ford ?
More like who doesn't. Pretty much any piston manufacturer that does custom pistons can.
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Re: Piston Question

Post by engineguyBill » Mon Feb 10, 2020 11:04 am

Coloradoracer wrote:
Sun Feb 09, 2020 11:04 pm
bigfoot wrote:
Sun Feb 09, 2020 5:07 pm
Who.makes custom pistons for a ford ?
More like who doesn't. Pretty much any piston manufacturer that does custom pistons can.
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Most, if not all, high performance piston manufacturers use very sophisticated CNC machines, therefore the designs they have available for specific applications is pretty much unlimited. Any of them will be able to supply the pistons you need.
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