The suspense was killing me, so I went to Summit's pages and did a search under the part numbers. Here is what I got:

TRW-L2399F60 - what Jughead has in his car....

Higher compression, longer life.

Piston, Forged, 4.310 in. Bore, 2-5/64, 1-3/16 Rings, .095 in. Dome, Each

Thanks to a special aluminum alloy that doesn't expand as much as other alloys, these Power Forged pistons are designed to fit tight, providing the stability and ring control you need plus the strength you want. Speed-Pro even added ribbed skirts to them for better oil retention and even includes new wrist pins!

Vendor Sealed Power
Product Line Speed-Pro Power Forged Pistons
Bore (in) 4.310
Bore (mm) (Not Specified)
Piston Material Forged aluminum
Piston Style Dome
Compression Distance (in) 1.645
Dome Height (in) 0.095
Dome Volume (cc) 13.80
Dish Volume (cc) (Not Specified)
Valve Reliefs None
Wrist Pin Style Press fit or floating
Pin Diameter (in) 0.9890
Top Ring Thickness 5/64 in.
Second Ring Thickness 5/64 in.
Oil Ring Thickness 3/16 in.
Quantity Sold individually.

Application Notes 1971 454 LS6 open chamber heads. Deck clearance: 0.020 in. Skirt clearance: 0.0040 in. Weight: 693g.

Notes Approximate compression ratios: 10.35:1 with 100.9cc, 9.83:1 with 106.9cc, 9.63:1 with 109.4cc, 9.09:1 with 116.9cc, and 8.94:1 with 119cc head.
________________________________________ ____________________


TRW-L2349F - the other piston mentioned on this thread

Higher compression, longer life.

Piston, Forged, 4.250 in. Bore, 2-5/64, 1-3/16 Rings, .265 in. Dome, Each

Thanks to a special aluminum alloy that doesn't expand as much as other alloys, these Power Forged pistons are designed to fit tight, providing the stability and ring control you need plus the strength you want. Speed-Pro even added ribbed skirts to them for better oil retention and even includes new wrist pins!

Vendor Sealed Power
Product Line Speed-Pro Power Forged Pistons
Bore (in) 4.250
Bore (mm) (Not Specified)
Piston Material Forged aluminum
Piston Style Dome
Compression Distance (in) 1.645
Dome Height (in) 0.265
Dome Volume (cc) 30.60
Dish Volume (cc) (Not Specified)
Valve Reliefs Single
Wrist Pin Style Press fit
Pin Diameter (in) 0.9890
Top Ring Thickness 5/64 in.
Second Ring Thickness 5/64 in.
Oil Ring Thickness 3/16 in.
Quantity Sold individually.


Application Notes 1970 LS6 closed chamber heads. Deck clearance: 0.020 in. Skirt clearance: 0.0040 in. Weight: 658g.

Notes Approximate compression ratios: 11.90:1 with 100.9cc, 11.18:1 with 106.9cc, 10.91:1 with 109.4cc, 10.18:1 with 116.9cc, and 9.99:1 with 199cc head.

So... looks like TRW (through Summit) would say Jughead is running a mechanical CR of just a bit under 9.63:1 with the pistons he has. If he had selected the taller dome pistons, he would have had a mechanical CR of just under 10.91:1.

This is all very interesting because if I decided to rebuild my original LS-4 454 of 1973 I would have the choice of ~9:1 with Jughead's pistons, or ~10:1 with pistons having the taller dome - I have iron heads (049 castings) with ~119cc combustion chambers. I wonder what I could get in the hypereutectic line... Summit, here I come for more research!

I hope we have solved this one! I love that motor!

 

the 2349 were used in the 1970 454 450 HP chevelle engine. the 2399 were used in the 1971 corvette 454 425 HP engine

 

Not to hijack the thread...but I had to look them up! Check this out for 0.030 overbore pistons:

STL-H110CP30

$39.69

Dominating the horsepower-per-dollar race.

Piston, Hypereutectic, 4.280 in. Bore, 2-1/16, 1-3/16 Rings, .340 in. Dome, Each

If you're looking for pistons with an unbeatable combination of performance and value, Speed-Pro hypereutectic pistons are for you. These pistons are manufactured from FM244 aluminum alloy, which contains 16 percent silicon for greater strength and wear resistance. They're also molded in the latest permanent-mold technology to ensure the precise fit and tight bore clearances that today's top engine builders demand. They're ideal for use in high-performance street, bracket racing, and Oval Track, and will work perfectly with normal ring end gaps.

Vendor Speed Pro
Product Line Speed-Pro Hypereutectic Pistons
Bore (in) 4.280
Bore (mm) (Not Specified)
Piston Material Hypereutectic aluminum
Piston Style Dome
Compression Distance (in) 1.640
Dome Height (in) 0.340
Dome Volume (cc) 33.00
Dish Volume (cc) (Not Specified)
Valve Reliefs Two
Wrist Pin Style Press fit or floating
Pin Diameter (in) 0.989
Top Ring Thickness 1/16 in.
Second Ring Thickness 1/16 in.
Oil Ring Thickness 3/16 in.
Quantity Sold individually.
Notes Piston has coated skirt.

Check out that dome height! The photo:

http://store.summitracing.com/defaul...+454&x=18&y=12

shows a serious dome! Wonder what that would do with my 119cc open chamber heads? The 33cc domes would give just a bit more than the approximate CR as the taller dome piston found on the 1970 LS-6 and discussed above. Any possible valve clearance issues? They show this piston for Gen IV, V and VI fitments and a set is about $80 cheaper than forged...

They also list a 0.060 piston with a 0.300 dome height and dome volume of 30.00cc

See also part number STL-H426CP for a standard bore (4.250) piston with only a 0.100 dome. Dome Volume (cc) 10.50. A 0.020 overbore piston is part number STL-H426CP20 and a 0.030 overbore is STL-H426CP30 both for $26.69 apiece!

Finessing that link gets you a total of 10 pages of these hypereutectic pistons - very interesting! Wonder what the total cost in parts and labor would be to rebuild my mill starting with $200 in pistons, and $150.00 flat tappet hydraulic cam...?

 

You beat me to that research Dave. That was my next step, but work got in the way again.

Wonder if the guy who recommended the 2399's to me knew about the 2349's and the difference? Hmmmmm..... If the price were the same why not go with the higher dome volume?

Thanks Clem, Norval, Dave and all the others for clearing up my piston hindsite research.

 

Jughead,

I think you got the best pistons for our gas these days, no sweat! Your pistons were a good recommendation. Any more CR and you would be sweating detonation with each tweak of the tuning parameters. Your 9.6 is much better than my 8.25 any day - and you have all the solid parts as well. Enjoy!

 

I got no picture with that link....just a Summit page??

 

Jughead,

Its possessed! No matter what it defaults to the basic screen. Input the part number in a search and it should come up that way... Go figure! Sorry about that...

 

Wow!


h110cp30




h110cp60