I have a friend that has a set of slivolite 1631 pistons. I would like to know if anybody has used them. I'm thinking of building a pretty hot street 455 for my 68 cutlass. I already have some edelbrock heads and engle JM22-25-10 cam. Would these pistons work?

 

Most guys will probably tell you go to with forged pistons instead. Those are a stock replacement cast piston. It does have the small dish, which should put your compression ratio in the ballpark for premium pump gas. They'll work, but with the money you've invested in Edelbrock heads you might as well throw down for some good forged pistons.

 

X2 plus iirc they're real short so you'll have a bunch of deck clearance unless you cut the crap out of the block. There goes part of your savings.

Jmo.

 

Good point. But what I keep reading on the forums is that all off-the-shelf Olds pistons - even forged ones - have too much deck clearance. Or is that only the case with the trusty SpeedPro L2323F?

 

Yes, the l2323 has a 1.735 comp distance. The kb and srp have a 1.750 conp distance. I know they're cheap but I'm not a fan of the 2323, there are better pistons out there for not much more.

 

The 2323 is intended as a stronger than stock replacement but with the same old school design. They were available 40 years ago and are still basically the same. If you are doing a mild rebuild, they are fine. If you do a seach, you can find "discussions" on this forum about more modern pistons and alloys. Just like other choices (cams, etc.), you can optimize for your intended use. In general, a higher performance, modern piston probably won't hurt, although softer alloys may experience ring groove wear sooner. A lower performance, old design piston can fail if stressed too hard, and lead to catastrophic failure. Having seen major failures from cast pistons, I would never recommend them for a performance engine.

 

Go with the KB IC886, best piston available for the money imo.

 

X2 I have IC886 in my engine and they are working really well. As cutlassefi said, they have 1.750" compression height so you don't have to deck the block much to work with the compression. The 1631's have a 1.720 compression height which really hurts your ability to create compression. Also, if you are buying new...you will note that the price is almost that of a high quality piston. I have done a lot of research on the KB pistons, which includes all of the Silvo-lite, ICON, and KB lines. Here are some numbers for you to consider:

**Compression calculations based on stock deck height (calculated for each piston compression distance), .040" thick /4.250 bore head gasket, .040" overbore, and 80 CC "E" heads.**

Keith Black 1631-040 $429.95
Cast dish piston (+16.00 CC)
Deck height (stock): 0.045"
Compression ratio: 9.230**

Keith Black KB277-040 $329.95
Hyperutectic dish piston (+15.00 CC)
Deck height (stock): 0.015"
Compression ratio: 9.819**

ICON IC886-040 $475.95
Forged flat top piston (+14.00 CC)
Deck height (stock): 0.015"
Compression ratio: 9.901**