H116CP vs H405CP

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summit has 116 for 311
...405s for 140....
 
116 can except floating pins. I think both are duplicate weight. almost a full number In compression. 405 valve reliefs are huge. Lose a lot of CCs. I have the 405s in a 360 no complaints. If I had to do it again I would spring for the 116s just for the compression.
 
The 116's are a Hyperutecic piston.
The 405's are regular cast.

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rumblefish360 said:
The 116's are a Hyperutecic piston.
The 405's are regular cast.

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The 116 pistons,are well worth it... Hell the car I know own: Previous owner: 6500-7000 rpm,with 125 -150 hits of spray.... Dingle ball honed block,stock oil pan... The pistons,lived through three scorched cranks@6500-6800 on top end (N20 assisted...) Personal experiences seen,& been in on: 116's if you plan to add more serious h.p.... Jmo.....
 
Thanks Valkman. The 405's have been around for ever. I was told and allways known them to be regular cast.
Otherwise, I see only this in there descriptions as different.

405 ...... 116
1.576 vs 1.660 in comp height
10cc .vs...5cc
 
Actually, the compression height in the Summit catalog is incorrect for the 405's; the H405CP's CH is actually 1.637". (The 1.576" CH applies to the dished top 405P piston.)

The 405's will drop around .75 point of compression ratio in a typical installation.

I do believe that the 'H' in front of the H405CP PN means hypereutectic.... just like 'L' in front of the PN meant forged in the old TRW PN system. Per Federal-Mogul, the H116CP and H405CP are made from the same FM-425 alloy.

Price difference? I can only speculate demand, lower CR, and the lack of pin ring grooves in the H450CP's....
 
And if you want the straight poop, here is a link to the Speed Pro performance parts catalog; the data is on page 84.
http://www.fme-cat.com/digipubZ/Speed-Pro-Performance-2015/D2891F88F8EC3ABA5B08E89DE34335DA/Speed-Pro Performance 2015 - digipubZ.pdf

And as for the hyper versus cast question, technically all hyper pistons ARE a cast process. They just use a lot stronger, lighter aluminum alloy. Due to this, I assume they are called hypers just to ID them clearly as a different cast piston from standard cast pistons.
 
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I belive the 4valve relief piston uses a off set wrist pin and the 2 valve relief uses no off set
 
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